Android Studio freezes on open Big Sur

Android Studio freezes on open Big Sur - android

So I've been using Android Studio 4.2 on my mac with no issue for quite some time, however today while in the middle of working on an app it froze for about 20 minutes until eventually I force quit it. Everytime i try reopening it it is immediatley frozen and shows this error:
My activity monitor also reports that it is using 950% of my CPU (I only have 6 cores). I have tried increasing the memory of Xmx like it says quite high, my system has 32gb of DDR4 so it should be fine but no change i make seems to actually do anything and the application just remains frozen.
Anyone have a similar issue or ideas of how to fix it?

Introduction:
This is the documentation that contains more specific details.
In your case use WAY1 of 2 ways to get to the configuration file.
WAY 1 - Reaching file through Directory + Documentation:
macOS
Syntax: ~/Library/Application Support/Google/<product><version>
Example: ~/Library/Application Support/Google/AndroidStudio4.1
Windows
Syntax: %APPDATA%\Google\<product><version>
Example: C:\Users\YourUserName\AppData\Roaming\Google\AndroidStudio4.1
Linux
Syntax: ~/.config/Google/<product><version>
Example: ~/.config/Google/AndroidStudio4.1
For Android Studio versions 4.0 and lower, configuration files are located in the following locations:
Windows: %USERPROFILE%\.CONFIGURATION_FOLDER
macOS: ~/Library/Preferences/CONFIGURATION_FOLDER
Linux: ~/.CONFIGURATION_FOLDER
There should be a studio64.exe.vmoptions file, you also can reach through the steps below.
WAY 2 - Reaching file in Android Studio:
You can create/edit this file by accessing "Edit Custom VM Options" from the "Help" menu at the top section.
General Settings for memory:
For quick access to increase your "Maximum heap size" I write this steps for better overview:
Click File > Settings from the menu bar (or Android Studio > Preferences on macOS).
Click Appearance & Behavior > System Settings > Memory Settings.
Adjust the heap sizes to match your desired amounts.
Click Apply.
Note: If you changed the heap size for the IDE, you must restart Android Studio before the new memory settings are applied.
After you reached the file studio64.exe.vmoptions:
Edit it in Android Studio (1. Headline) or right click it and "Edit" with Notepad or Textdocument. Now the studio64.exe.vmoptions should contain following line of codes:
-Xms128m
-Xmx4096m
-XX:MaxPermSize=1024m
-XX:ReservedCodeCacheSize=200m
-XX:+UseCompressedOops
Xmx specifies the maximum memory allocation pool for a Java Virtual Machine (JVM), while Xms specifies the initial memory allocation pool. Your JVM will be started with Xms amount of memory and will be able to use a maximum of Xmx amount of memory.
Save the studio64.exe.vmoptions file and restart Android Studio.
Restart IDE and clear your Cache:
Since Android Studio is based on IntelliJ, the option should be in the same place. It's a feature you would seldom use unless your file caches went ballistic (and that can happen every now and then).
Under File > Invalidate Caches/Restart, you'll find an option that lets you either invalidate the caches (and you'll have to rebuild indexes again), or just restart the IDE.
What in this specific case helped:
#Quinn did a reinstallation because he had no access inside android studio. That fixed the cache issue of course also.

Related

How to Speed up Android Studio 3.0

I just want to ask "How can I speed up my Android Studio?". Though I do own:
Dell Inspiron 15R
12GB of RAM Core i7 (N5537),
these specs may look cool but still I am unable to working on Android Studio in Peace. As my Android Studio takes a lot of time when I reboot my machine and start the Android studio, its indexing process is way too long, the gradle build process is also way too laggy!
Even whenever I try to run my app on any device say on Virtual Device or any other real device it takes a lot of time, to switch between .java to .xml files is also way too long! For the most of times the Android Studio also stuck and hangs on different events especially on Gradle Build or refreshing the project and indexing the project files!

For the above issue, I have done some work around to speed up my Android Studio. In other words the results are just boosted my Android Studio!
Step 1 Increase Windows Virtual Memory
Goto Computer, Right Click and Choose Properties
Select Advanced System Settings
Select Performance Settings
Select the Advanced tab, and click the Change button on Virtual Memory Section
Uncheck the Automatically manage paging file size for all drives
Choose your desired drive to use as a Virtual Memory Part
Check the Custom Size Radio Box
Insert the Inital Size (MBs), this step is important! For me I have about 150GBs free in my C Drive so I set the initial size to 40GB!
Set the Maximum Size (MBs), I have set it to 50GB because have a lot of free space!
Click Set, then Ok
Step 2 Edit Custom VM Options in Android Studio
Start Android Studio
Click Help
Select Edit Custom VM Options
Click Yes to the Next dialog (If file didn't exists already it will prompt you to create one)
Add these Lines to that Opened File:
# custom Android Studio VM options, see http://tools.android.com/tech-docs/configuration
-Xms1024m
-Xmx4096m *****INCREASE THIS TO MAXIMUM OF YOUR RAM
-XX:MaxPermSize=1024m
-XX:ReservedCodeCacheSize=1024m
-XX:+UseCompressedOops
-XX:+HeapDumpOnOutOfMemoryError
-Dfile.encoding=UTF-8
(You Should increase these values to the maximum of your machine resource, the above is for my own machine settings)
Step 3
Simply Invalidate Caches and Restart Your Android Studio
Don't forget to edit your startup programs and service, you have to disable all junk/useless or non important services at the startup and reboot! (This step is also very important)
Give your machine a Reboot
For me these all steps are a great workaround, so you should give them a try
Please Note that you should set all the said values according to your machine hardware and software resources
Thanks

Config + SSD made a huge difference!
Tweaking Paging Size, Clearing Temp Files and Cache do help but you wouldn't not have taken time to post here for saving a few seconds.
For marginal performance boost, We upgraded the machine and it's worth it.
Machine Specs: Alienware-i7 7820HK|16GB RAM|256GB PCie SSD|1TB HDD
Software Config: Android Studio in SSD|SDK in HDD|Project Folder in HDD
Clock Time to load Android Studio: 9s
Clock Time to create a new empty project: 20s till Gradle Build Finished
Clock Time to open an empty project: Less than 5s till Gradle Build Finished
Clock Time to open Android Studio; create a new empty project: 40s till Gradle Build Finished
If you could keep track and manage Android SDK properly, and predominantly use AS alone, we recommend an All-in-SSD approach.
Regards.

What SO are you using? I'm using the same version of Android Studio on an Acer with Windows 10, 8gb of RAM and i5-7200U, and I'm not facing these problems. Try to defrag your disk, or use a SSD, it helps a lot.

To prevent the excessive "Indexing..." when launching Android Studio (with multiple projects open), you can switch on File -> "Power Save Mode". This makes it start up much faster. It also saves a lot of CPU in general, for example when typing code. You can switch it back on when you need the live inspections.
More info: https://jwhh.com/2013/06/07/android-studio-power-save-mode/

not enough memory to perform requested operation-Android studio Out of memory issue [duplicate]

I've been using Android Studio for 3 months now and one of the apps I started on it has become fairly large. The memory usage indicated at the bottom right of the program says my allocated heap is maxed at 494M.
When I start to change the XML files my memory usage quickly reaches that cap and the IDE crashes with an Out Of Memory error like this.
I've tried to increase the heap size using this but so far there has been no effect.
I've looked at dozens of articles and other questions on how to increase the heap size but none of their answers are working. No matter what I do to the VMOPTIONS or the IDE settings the heap size never increases. I believe I am editting the correct file for the VMOPTIONS because if I purposely give it an invalid command Android Studio complains about it and doesn't start.
I'm using windows 7 - 64 bit and have 16GB RAM.
Has anyone else had this problem with Android Studio? And were you able to fix it?

-------EDIT--------
Android Studio 2.0 and above, you can create/edit this file by accessing "Edit Custom VM Options" from the Help menu.
-------ORIGINAL ANSWER--------
Open file located at
/Applications/Android\ Studio.app/Contents/bin/studio.vmoptions
Change the content to
-Xms128m
-Xmx4096m
-XX:MaxPermSize=1024m
-XX:ReservedCodeCacheSize=200m
-XX:+UseCompressedOops
Xmx specifies the maximum memory allocation pool for a Java Virtual Machine (JVM), while Xms specifies the initial memory allocation pool. Your JVM will be started with Xms amount of memory and will be able to use a maximum of Xmx amount of memory.
Save the studio.vmoptions file and restart Android Studio.
Note:
If you changed the heap size for the IDE, you must restart Android Studio before the new memory settings are applied. (source)

I looked at my Environment Variables and had a System Variable called _JAVA_OPTIONS with the value -Xms256m -Xmx512m, after changing this to -Xms256m -Xmx1024m the max heap size increased accordingly.

Or, you can go to your android-studio\bin folder and change these -Xmx and -Xms values in studio.exe.vmoptions or studio64.exe.vmoptions files (depending on which version you are running).

You should not edit any files in the IDE installation directory. Instead, you can customize the attributes by creating your own .properties or .vmoptions files in the following directories. (This has been possible on some platforms before, but it required you to copy and change the entire contents of the files. With the latest changes these properties are now additive instead such that you can set just the attributes you care about, and the rest will use the defaults from the IDE installation).
Note: As of Android Studio 2.0, you can create/edit this file by accessing the "Edit Custom VM Options" file from the Help menu.
http://tools.android.com/tech-docs/configuration

I increased my memory following the next Google documentation:
http://tools.android.com/tech-docs/configuration
By default Android Studio is assigned a max of 750Mb, I changed to 2048Mb.
I tried what google described but for me the only thing that it worked was to use an environment variable. I will describe what I did:
First I created a directory that I called .AndroidStudioSettings,
mkdir .AndroidStudioSettings
Then I created a file called studio.vmoptions , and I put in that file the following content:
-Xms256m
-Xmx2048m
-XX:MaxPermSize=512m
-XX:ReservedCodeCacheSize=128m
-XX:+UseCompressedOops
Then I added the STUDIO_VM_OPTIONS environment variables in my .profile file:
export STUDIO_VM_OPTIONS=/Users/youruser/.AndroidStudioSettings/studio.vmoptions
Then I reload my .profile:
source ~/.profile
And finally I open Android Studio:
open /Applications/Android\ Studio.app
And now as you can see using the status bar , I have more than 2000 MB available for Android Studio:
You can customize your values according to your need in my case 2048Mb is enough.
UPDATE : Android Studio 2.0 let's you modify this file by accessing "Edit Custom VM Options" from the Help menu, just copy and paste the variables you might want to keep in order to increase it for everversion you might have on your box.

If you are using MAC BOOK, this option is available inside Applications -> Right click Android Studio then choose Show Package contents -> bin.
or
open -e /Applications/Android\ Studio.app/Contents/bin/studio.vmoptions
Then increase Xmx value
-Xms128m
-Xmx2048m
-XX:MaxPermSize=350m
-XX:ReservedCodeCacheSize=64m
-XX:+UseCodeCacheFlushing
-XX:+UseCompressedOops
Now your Android Studio will be super-fast.

Android Studio 3.1 has option to edit your customize virtual memory options.
You can go Android Studio > Help > Edit Custom VM Options
Then paste below settings code to studio64.exe.vmoptions file & Save it.
file location : "\Users\username\.AndroidStudio3.**\config\"
-Xms128m
-Xmx4096m
-XX:MaxPermSize=1024m
-XX:ReservedCodeCacheSize=200m
-XX:+UseCompressedOops

You can try any one of the following
1)Change the gradle.properties file and change the heap size as per your requirement.
If org.gradle.jvmargs=-Xmx2048M is not sufficient then change to 4096 as given
org.gradle.jvmargs=-Xmx4096M
2)"Edit Custom VM Options" from the Help menu.
It will open studio.vmoptions / studio64.exe.vmoptions file.
Change the content to
-Xms128m
-Xmx4096m
-XX:MaxPermSize=1024m
-XX:ReservedCodeCacheSize=200m
-XX:+UseCompressedOops
Save the the file and restart Android Studio.

Note: I now this is not the answer for the post, but maybe this will be helpful for some one that is looking.
If Nothing of this works for you, try on a Mac this to see if helps you, in the last version of Android Studio, the studio.vmoptions is inside the AndroidStudio.app in your Applications folder.
So right click or ctrl click on your AndroidStudio.App and then select show package content the studio.vmoptions is in:
Contents/bin/studio.vmoptions
Replace or change it and you will get all the RAM you need.
Regards.

I tried the _JAVA_OPTIONS thing but it wasn't working for me still.
In the end, what worked for me was the following:
Launching studio64.exe instead of the studio.exe(I've got a 64-bits machine).
Add/Change the following values in "studio64.exe.vmoptions":
-Xms2048m
-Xmx2048m
-XX:MaxPermSize=1024m
-XX:+CMSClassUnloadingEnabled
-XX:+CMSPermGenSweepingEnabled
-XX:+HeapDumpOnOutOfMemoryError
-Dfile.encoding=utf-8

There are a lot of answers that are now outdated. The desired way of changing the heap size for Android Studio recently changed.
Users should now create their own vmoptions file in one of the following directories;
Windows:
%USERPROFILE%\.{FOLDER_NAME}\studio64.exe.vmoptions
Mac:
~/Library/Preferences/{FOLDER_NAME}/studio.vmoptions
Linux:
~/.{FOLDER_NAME}/studio.vmoptions and/or ~/.{FOLDER_NAME}/studio64.vmoptions
The contents of the newly created *.vmoptions file should be:
-Xms128m
-Xmx750m
-XX:MaxPermSize=350m
-XX:ReservedCodeCacheSize=96m
-XX:+UseCompressedOops
To increase the RAM allotment change -XmX750m to another value.
Full instructions can be found here:
http://tools.android.com/tech-docs/configuration

First check how much memory allocated for your android studio
to check that follow this steps :
File -> Settings->Appearance & Behavior->Appearance
then check the show memory indicator option like below image red highlighted part
In my case my RAM is 12Gb so i have allocated memory for android studio 6gb .To edit that follow this steps
Help->Edit custom VM options
-Xmx6g
In my case, i have set it 6gb because my pc ram is 12 GB. Its upto you how much memory you want to allocate to your android studio

This is how you change the heap size currently in Android Studio 3.6.1
On Windows in your Android Studio:
Select File -> Settings (the popup below will be displayed)
Select Appearance & Behavior
Select System Settings
Select Memory Settings
Then change the IDE Heap Size settings to your desired value
On Mac:
Select Android Studio
Select Preferences
The same pop up will appear. However, this time on the Mac its called Preferences.
Follow the same steps as the Windows version of Android Studio to adjust the heap size wants the Preferences dialog has been displayed

On Mac OSX one can easily change heap size by going to first menu item, Android Studio > preference > System Settings (left menu) > Memory Settings and change heap size there in the dialog.

On Windows 7, the configuration files at [INSTALL-LOCATION]\bin seem to be ignored. Per the following Google documentation, the file to be modified should be here: %USERPROFILE%\.AndroidStudio\studio[64].exe.vmoptions
http://tools.android.com/tech-docs/configuration
Odd that there is no such file upon a clean install of Android Studio 1.1 from the developer site. And they are in the old (ignored) location. Once I copy the file (studio.exe.vmoptions in my case) over and modify it, the change is respected.
However, the fun doesn't stop there. There's an upper value for -Xmx which may be related to the amount of memory in your system. I just bumped my machine's memory from 4Gb to 16Gb, and assumed I could set -Xmx to 2048m, but I found that if I set it to anything larger than 1500m, Android Studio would silently fail to launch with no indication at all as to why. I have more RAM on the way, so it will be interesting to see if I can increase the value at that point.
I hope this additional information is helpful. While all of the above replies were undoubtedly true at one point (and may still be in some environments), I found that this was the only approach that increased the memory used by AS for me.

Open studio.vmoptions and change JVM options
studio.vmoptions locates at /Applications/Android\ Studio.app/bin/studio.vmoptions (Mac OS). In my machine, it looks like
-Xms128m
-Xmx800m
-XX:MaxPermSize=350m
-XX:ReservedCodeCacheSize=64m
-XX:+UseCodeCacheFlushing
-XX:+UseCompressedOops
Change to
-Xms256m
-Xmx1024m
-XX:MaxPermSize=350m
-XX:ReservedCodeCacheSize=64m
-XX:+UseCodeCacheFlushing
-XX:+UseCompressedOops
And restart Android Studio
See more Android Studio website

I found on on Windows 7/8 (64-bit), as of Android Studio 1.1.0:
[INSTALL_DIR]\bin\studio64.exe.vmoptions be used (if it exists), otherwise it would always fall back to %USERPROFILE%.\AndroidStudio\studio[64].exe.vmoptions
If you want the settings managed from %USERPROFILE%.\AndroidStudio\studio[64].exe.vmoptions, just delete the one in the installation directory.

Go in the Gradle Scripts -> local.properties and paste this
`org.gradle.jvmargs=-XX\:MaxHeapSize\=512m -Xmx512m`
, if you want to change it to 512. Hope it works !

you are not supposed to modify the bin/studio.exe.vmoptions file, which will be verified during applying update patch.
Solutions are here http://tools.android.com/tech-docs/configuration
copy that file into following location, then change the -Xmx1280m to whatever you want.
Windows:
%USERPROFILE%\.{FOLDER_NAME}\studio.exe.vmoptions
and/or
%USERPROFILE%\.{FOLDER_NAME}\studio64.exe.vmoptions
%USERPROFILE%\.{FOLDER_NAME}\idea.properties
Mac:
~/Library/Preferences/{FOLDER_NAME}/studio.vmoptions
~/Library/Preferences/{FOLDER_NAME}/idea.properties
Linux:
~/.{FOLDER_NAME}/studio.vmoptions
and/or
~/.{FOLDER_NAME}/studio64.vmoptions
~/.{FOLDER_NAME}/idea.properties

Had this Xms and Xmx memory low issue happen to me any time I was working with the XML. I also tried increasing this memory, only to find that it just took a little longer for it to happen again.
After getting very frustrated and almost deciding to convert all my current projects back over to Eclipse, which I did not want to do, I figured out what was causing it and was able to repeat this failure and prevent it every time.
While editing the XML in (Text view), and using the "Preview" render view, this causes the loss of memory, every time. Turning off "Preview" and using the Design tab to render the screen only, I am able to use Android Studio all day long, with no crash.
I wish this could be fixed for good, because it would be very nice to use the "Preview" render while editing the XML, however I am glad I can keep using Android Studio.

On Ubuntu, it's straight forward, clicking Help > Edit Custom VM Options
. The IDE asks whether to create for you a file, click OK.
An empty studio64.vmoptions file is create and paste the following variables:
-Xms128m
-Xmx4096m
-XX:MaxPermSize=1024m
-XX:ReservedCodeCacheSize=200m
-XX:+UseCompressedOops
Restart the IDE, the Max Heap Size is increased to: 4,062M

May help someone that get this problem:
I edit studio64.exe.vmoptions file, but failed to save.
So I opened this file with Notepad++ in Run as Administrator mode and then saved successfully.

IF by changing or creating the .studio.exe.vmoptions doesn't work, then try changing the gradle.properties file and change the heap size as per your requirement.
It really worked for me on my Windows 7 with 4Gb RAM and Android Studio 2.2 install on it.
Working properly with no error and displaying 'Gradle Sync complete'

-Xms256m
-Xmx2048m
-XX:MaxPermSize=512m
-XX:ReservedCodeCacheSize=128m
-XX:+UseCompressedOops

As of 2022, you may check this link here.
https://developer.android.com/studio/intro/studio-config.html
Windows
Syntax: %APPDATA%\Google\<product><version>
Example: C:\Users\YourUserName\AppData\Roaming\Google\AndroidStudio4.1
macOS
Syntax: ~/Library/Application Support/Google/<product><version>
Example: ~/Library/Application Support/Google/AndroidStudio4.1

Android studio 2.2.3 is too slow when it starts

Android studio is too slow when it starts. It is needed to wait few minutes before the loading pops up. I'm not talking about the gradle building, but android itself...
This is not my first android studio... I also used android studio(maybe 2.2.1 or 2.2.0) before I formatted my laptop, thus I know how much time it needs to show that loading screen.
For details I use 6th generation I5 cpu, 8GB Ram, and ssd.

You need to upgrade your PC though but there are few things you can do to make it faster
Increase the memory size of Android Studio:**
Open the file located at /bin/studio.vmoptions and Change the content from
-Xms128m
-Xmx800m
to
-Xms256m
-Xmx1024m
Xms specifies the initial memory allocation pool. Your JVM will be started with Xms amount of memory and will be able to use a maximum of Xmx amount of memory.
Save the studio.vmoptions file and restart Android Studio.
Improve Gradle performance:**
Create a file named gradle.properties in
/home/<username>/.gradle/ (Linux)
/Users/<username>/.gradle/ (Mac)
C:\Users\<username>\.gradle (Windows)
and add the line:
org.gradle.daemon=true
This helps a lot, with org.gradle.daemon set to true Gradle reuses computations from previous builds and cache information about project structure, files, tasks etc. in memory so it won’t have to start up the entire Gradle application every time.

In order to increase the speed of the android studio you need to allocated extra RAM memory to android studio(Vm option) as mentioned in the link ---> config android studio vm option.In the official blog it state that you can not edit it directly.
Note that you should never directly edit the studio.vmoptions file found inside the Android Studio program folder. While you can access the file to view Studio's default VM options, editing only your own studio.vmoptions file ensures that you don't override important default settings for Android Studio. Therefore, in your studio.vmoptions file, override only the attributes you care about and allow Android Studio to continue using default values for any attributes you have not changed

Android studio 2.2 running very slow in windows 10 [duplicate]

I recently upgraded from Eclipse to Android Studio and I'm not really liking the experience. I'm comparing them both on a Windows 7 64 bit ultimate with 16GB of ram and Intel i7 4770 running NVidia Geforce 780 with the latest NVidia drivers if it matters and I'm running the latest JDK and the latest Android Studio.
The Android Studio is very slow in building the project which I can live with but it's also extremely resource intensive and sometimes slows down the PC to a crawl.
Whenever I'm building or running anything in AS, my PC seems to become extremely sluggish. It also causes flickering of screen and occasionally blanking my second monitor if I click on "Gradle build running" spinner which I find very odd. The RAM usage also shoots up to ~3GB which I find excessive for doing nothing (this is when it's idle after a few builds).
In addition, the panels at the bottom of AS keep jumping around which is a horrible user experience (moves from Android to Messages to Version Control or anything else on an ad-hoc basis depending on what's happening which is very, very annoying).
What I would like to know is basically:
1) How do I make Android Studio run better? I may be doing something wrong or missing some updates that I'm not aware of and I'm sure others have also noticed these behaviors and have found some solutions to it.
2) How do I "pin" the bottom panels so that they don't jump around and instead, let me, the user, navigate to them when I wish to instead of automatically switching them?
Many thanks and my apologies again if it's not the correct place for these questions.
Edit 1
Some more comments:
I'm using the latest stable build as of today. The build is Android Studio 1.2.2 Build # AI-141.1980579, Build on June 3, 2015
The behavior happens when using either Java 7 or 8. It doesn't appear to be related to the version of Java.
I am not using Presentation Mode. Just the vanilla view.
Doing the changes to the build configuration (thanks to #Blackbelt and his answer) appears to have helped with the build but the other problems with sluggishness and general user experience remain.

to sum it up
1) in AndroidStudio's settings > compile enable checkbox named Compile independent modules in parallel.
2) Under Help> Edit Custom VM Options I have:
-Xms1024m
-Xmx4096m # <------ increase this to most of your RAM
-XX:MaxPermSize=1024m
-XX:ReservedCodeCacheSize=440m
-XX:+UseCompressedOops
-XX:-HeapDumpOnOutOfMemoryError
-Dfile.encoding=UTF-8
P.S. - Some people say Note, instead of VM options, it's better to combine can be overriden by combining those lines into one line single command in gradle.properties, like this :
org.gradle.jvmargs=-Xms1024m -Xmx4096m ......
3) I have an old dual core with 4GB ram, running ubuntu. Qs command line option I have only --offline (which specifies that the build should operate without accessing network resources). I also enabled the remaining checkboxes and now it's running ok:
Make project automatically
Use in-process building Configure on demand
Check the AndroidStudio's settings, under compile that the checkbox Compile independent modules in parallel is enabled.
Under Vmoptions I have
-Xmx2048m -XX:MaxPermSize=1024
I have an old dual core with 4GB ram, running ubuntu. Qs commandline option I have only --offline , which specifies that the build should operate without accessing network resources. I enabled also the remaining checkboxes:
Make project automatically
Use in-process building
Configure on demand
and it is running ok
Edit
It is possible to provide additional options through studio.vmoptions located at (just replace X.X with version):
Windows: go to %USERPROFILE%\.AndroidStudioX.X\studio.exe.vmoptions (or studio64.exe.vmoptions)
Mac: ~/Library/Preferences/.AndroidStudioX.X/studio.vmoptions
Linux: ~/.AndroidStudioX.X/studio.vmoptions (and/or studio64.vmoptions)
Increasing the value of -Xmx should help a lot. E.g
-Xms1024m
-Xmx4096m
-XX:MaxPermSize=1024m
-XX:ReservedCodeCacheSize=256m
-XX:+UseCompressedOops
will assign 4G as max heap, with initial value of 1G
Edit:
On windows the defaults are stored into C:\Program Files\Android\Android Studio\bin\*.vmoptions. The IDE allows you to tweak those values through Help->Edit Custom VM options (thanks to #Code-Read for pointing it out).
EDIT 2:
Android studio 3.5 makes easier to change same of those values. Just go to:
Preferences > Appearance & Behavior > System Settings > Memory Settings

Tips to make android studio fast:
Enable Offline Work:
Click File -> Settings. Search for "gradle" and click in Offline work box.
Go to Compiler (in same settings dialog just below Gradle) and add --offline to Command-line Options text box.
Improve Gradle Performance
gradle can be optimized too. The easy way is to modify the settings in global gradle.properties (create it if not exists in the following folders: Windows - C:\users\your_name\.gradle\; Linux- /home/<username>/.gradle/; Mac- /Users/<username>/.gradle/; ) and in that file, add these two lines:
org.gradle.daemon=true
org.gradle.parallel=true
For More: http://www.viralandroid.com/2015/08/how-to-make-android-studio-fast.html

I detected another reason - Thumbs.db, which affected performance badly.
Go to File > Settings > Editor > File Types and in field Ignore files and folders add this: Thumbs.db;
Now, Android Studio runs like a charm.

Adding more memory helped me:
Click "Help"
Edit Custom VM Options
Android Studio 2.1.2 Edit Custom VM Options:
Change values
like below:
-Xms512m
-Xmx2560m
-XX:MaxPermSize=700m
-XX:ReservedCodeCacheSize=480m
-XX:+UseCompressedOops
Restart Android Studio

Recommendations:
MUST TO SAY: if you have any chance, spend some money for better PC(cpu),
it's Most important ..
Tweaks:
Some people say, that OS (Operating System) might cause much slowness. For example, XP or LINUX (or etc) was mentioned to perform 70% faster (don't know why..).
Disable VCS by File > Settings > Plugins and disable the following things :
CVS Integration; Git Integration; GitHub; Google Cloud ... things; Subversion Integration; hg4idea;
Editor is a resource eating too (especially on Large Monitors) and slow. Make it much much faster: click Help > Edit custom VM options and add these lines :
-Dsun.java2d.d3d=false
-Dsun.java2d.opengl=true
save it and Restart Android Studio.
If Android Studio has a proxy server setting and can't reach the server then it takes a long time to build and waiting for a timeout. Removing it helps much. File > Settings > Appearance & Behavior > System settings > HTTP Proxy.
Another Useful quote (from article):
Modules are expensive… On my current project I had to build some libraries from scratch and had to fork some that almost fitted my needs but not quite! If that modules are not constantly modified, it’s important to have this into consideration: the time needed to compile them from scratch, or even to check if the previous individual module build is up-to-date, can be up to almost 4x greater than to simply load that dependency as a binary .jar/.aar.
Hint: run the gradle build -profile for an HTML report showing where
the time goes regarding the build process.
Note: keep that “unnecessary” modules in your version control system
for the eventuallity of a quickfix/improvement in that dependency.
In your Gradle build script, use only
specific Google Service, like: compile 'com.google.android.gms:play-services-maps:...'
Instead of full Google Library: compile 'com.google.android.gms:play-services:...'
(Compile time goes from 2 minutes to around 25 seconds).
Gradle configures every project before executing tasks, regardless of whether the project is actually needed for the particular build. In global gradle.properties adding this will help much: org.gradle.configureondemand=true
Surprisingly, some people say , they solved problem by reducing: 1) heapsizes to -Xmx256m (instead of higher values); 2) Emulator Ram-size (from Edit AVD > Advanced Settings);
Everyday Recommendations:
Don't run multiple projects simultaneously.
Don't close emulator after using once (use same emulator for running app each time; If you test large apps, better to use a real mobile phone instead of emulator).
clean your project every time after running your app in emulator - click Build > Clean Project (or Rebuild), you can use keyboard shortcut.

An anti-virus is causing the slow-down
In one particular system I looked at, this issue was caused by an over-zealous anti-virus that was interfering with Gradle, the build manager for Android Studio. It seems every time Gradle was "touching" a .jar file, the virus checker was unzipping the .jar and scanning it for viruses first. The Gradle build could only continue once the unzipping and scan was complete, thus leading to very long build times (5 min plus). Since Android Studio, by default, runs a Gradle build when you start up, it manifests as an extremely slow start-up.
The problem is extremely easy to check for:
While you are experiencing the symptoms of a slow Android Studio, press Ctrl- Alt-Delete and open Windows Task Manager.
Click on the Processes tab to see the active processes and sort by CPU. If you see an anti-virus taking significant amounts of CPU percentage intermittently while Android Studio appears to be loading, it is likely to be the same issue.
You can verify further by looking at the scan logs of the anti-virus to see if it is indeed, examining the .jar files.
To solve this, you will have to add the correct directories to the "excluded folders" of your anti-virus. Assume that your Windows username is "Username" and you have installed Android Studio on C: drive. You would then request to exclude from the virus check the following directories:
C:\Users\Username\.android
C:\Users\Username\.AndroidStudio2.2
C:\Users\Username\.gradle
C:\Users\Username\.m2
C:\Users\Username\AppData\Local\Android\Sdk
Please note that you may need to take additional security precautions if you exclude these directories and you should co-operate with your security department in the workplace. This may involve setting up your own Maven repository if deemed necessary.
(I am aware that this is a late answer, but none of the previous answers have addressed this potential issue)

The best way to boost up android studio runtime performance is to use SSD Drive. It will boost the performance as very much. I did all the above things and felt I should go for new laptop, but suddenly I came to know about SSD Drive and I tried it. Its Much Much better.....

Starting from Android Studio 3.5 some of the settings can be configured via:
Preferences > Appearance & Behavior > System Settings > Memory Settings

As you are learning, performance problems with AS are not trivial to diagnose! In my case, an array of 9215-character-long strings (see below) was causing AS to dump threads every time I typed a few characters. The thread dump in turn caused AS to freeze for many seconds at a time. This bug appeared in the Windows 64 bit release of AS 2.2, still occurs in 2.2.1, but was not present in 2.1.
Finding out that long strings were causing my lockups involved a lot of trial and error. But, I learned a lot in the process, to wit:
idea.log contains excellent diagnostics (Help->Show Log in Explorer);
If you see extreme, but intermittent slowdowns, suspect AS is dumping threads. This will be reported in idea.log. If threads are being dumped, the dumps will tell what code AS was executing when the problem occurred;
Find out whether the problem occurs in other projects. If not:
Look for unusual content in the project file you are editing when it happens (atypical indentation, long lines, overall size, special characters, etc.);
Try exporting settings from another project (File->Export Settings) and importing them to the problem project (File->Import Settings);
If so:
If threads were dumped, consult these and text in idea.log near in time to the dump notices for details;
Consult idea.log for messages about memory consumption and see other answers to this question such as https://stackoverflow.com/a/30818099/5025060 for advice regarding memory and other tunables.
BTW, for the present I have worked around the problem I describe above by moving my long strings into a separate file (a new class containing only the array itself). I try not to edit this file with AS:
package com.code_read.numerous;
// Stored in this separate file as workaround for but in Android Studio 2.2 and 2.2.1:
public class numstrings {
// Array of long random numbers, pregenerated to save CPU:
public static String[] numStrings = {
"1994801747005006843714201906880253696522949748985326677038709789185967438890341338611514272350885327622521908597157249370879944242140791335147432026134824720740049422401084226720133085129616983462326179050524905784581311738181639680883063657881249352299873899633102883079263518571839777601914176182096937173423830949774911901873302923856537838861459241472638781656098601555557408806160767422350665857755259469740684280328594623487891856649804661311584819889021607692403556050362471700089064611736323716743369045566550043297886962382238972346803574929493941865243842713784425065710461253862400171476763748485152265818223228738602947583646715233019327072692198843646688882967198106819142520249672265351399800388354025004692933034453856310668983827639931666936938916009440796386813973983672644014904413778331910858768917928873281368985209021482683952081386327659051891824451191925471319812621259979532306720944409709629735970343666731869954034316405565091456617722086997643045624243562108799691470340913893507767740993074136786407728485289296107929206890085077392507082912846952398146667121278744316903425134851243985929053983393147017505604434867248844096413015812503568125982543971955820413742070505248547214107175178265142568846059329034952916141529583930414467212444502036542524617924549772053409654734421683144469210875898562685596220560192157362075125532254942822533743408921908929641678544642703503594074980743406344521590503045906227137661428271960131113277418339143973111082350228713746798378222516362568169460000318016326976650293881476430655341696576379350118649066871443832472485758673939055476560230899083569553163276996789822628817697832818790241925450785958610992913835742648625121141300671379995864219490095867782136575514562312355082557943388653539768674297724271799184606163161313425019700484444819066035391880746315112526037089535247330068932135889561140507915603287185585871635986744215882173808096949176219939887238887334722353676565435219071025041608367345267066726720611291582289439439612089674948098814236544937685399901819502531986223218568943243997435066143130178791000919086345646088512272404095142569642614311667312552162499433826639585939112523653901049019510191636415536463869158678443168682968868561220976836056328690236345809499227235279493834218592602537877502486405864881552717053543189719307053056816394385005456307948699769878097421584471193206705541786346321099838491406911644862584829227001243533889390554091269606738674355046945345379729891849274972515399708243414881495449271744164313389780954995533638662175281443803394130967885827452291651790131097465299047904416340363246566292581832443962169777366091769276178419242913042363067255854810045262072561262497882054411067404793283085662036333037852105588278019261992793348698449219702477068967045885370794330720954454245355308540958222825316492004461258554509240961981517193582846294254836203336025137341304408025995714446392364687275863279014867118285477989325893247306751836367684953368894347431163738410742861211279475477541038825000059684941207285338893011165006513877204119377603716863643207293943901695444037969482551395887698689973125887804501587905607600937731808334970542039068964636903217786176395609646375619848654481970892367791860451203264612717833201133436864904072748056378537459970985749678435355552142278067182133232365792401224495951897760268571948611922604355922375837544987778238789194623584535535254680741527344169337882616511606089113581933652057746108337126592702595374689971756756111067694717736394911229561144105722719640374962520460026331390332290940671029266628430146882434958107641078763479395158409336392937553836429741828629803422700786051415863869569938234773023177898087231140282878699043621587286853385344543538863846680176575820030898369777652851615637670515908885347304910473243565872464918739636453311477591108155484066595590866237425656891311608168730789287191508068168280943391188623809857749891974336067657666981798722169247806143519254933881034442491694639196165306619163668670589218273202395456712339218153069379599709284877699907448943232601989425999495118291205271538894703052937474218759295979078630049366622491626168635389072593839896835573511248649620277111886034197292219150370416314231865599090073037180634352088129486602845851146031025385976117573877636799889628310244685157927781259284499624581204368313487038197704984151463672324235759633466623345866962841874409357386712655972436268785904826885404662832395057952852032223129527277689869930541833537646239889750795361522746356839955237437406742371092053189844778455591438073185335922355656078594182187644269204458708004487782896518372050828673610973903722768428111606169275709807883199484042341569039148939656571042895897900511235866082925245585957414155456211557703308834984738389589467066787565024602550298595008588579506402296897017756315583049561492731227012775126346716028440596381695862547286594079673622699591054192184165670931182439575423162742954983282488173948326304669845817443923349833883463090802279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}

It's not compiling that's hurting me here, it's the typing. I could disable all the smart features and be back to notepad++ like TomTsagk suggested in a comment. For today I need more cores and RAM.
Playing devil's advocate I'd argue that typing shouldn't require a 16Gb PC octacore PC. Liked Sajan Rana's advice but things are so slow here it felt mostly a placebo.
To be fair I am using 1.4RC1, which is just short of being in the stable branch. Turning the internet off helped a little. The new feature of simultaneous Design (Preview) and Text views working with XML layouts is very helpful.
No, it is ridiculous. Never leave the stable channel.

This answer pertains to slow Gradle build speeds for Windows 10 after you've already gotten the Xmx and Xms memory settings straightened out.
Windows Defender
As far as Windows Defender is concerned it's simply not enough to add folders / files to the Windows Defender exclusion list via "Files" or "Folders".
You must add directories pertaining to Android Studio / Gradle / Java (embedded JDK or Oracle JDK) as "Process" exclusions to Windows Defender :
Go through the answer by David Rawson
During a Gradle build... monitor the Windows Task Manager's Processes
To Windows Defender, add "Process" exclusions for directories containing the file/executable you see utilizing the CPU during a build associated with Android Studio / Gradle
This obviously comes with security implications.
The following describes more details pertaining to using a "Process" exclusion in Windows Defender (as opposed to adding a simple "File" or "Folder" exclusion) :
A file name with full path causes the particular binary file to be excluded, i.e. any files it touches, regardless of where the file is located, will not be scanned by Windows Defender. A file name without any path causes any binary file with this file name to be excluded regardless of its location. A path followed by a "*" (e.g. c:\my\private\tools*) causes any binaries under this path to be excluded. Any files touched by these processes will be excluded. This is different from a path exclusion, where files touched by any process under the excluded path is excluded.
The key here being....adding these exclusions as "Process" type exclusions takes into account "files the binary touches" as opposed to manually finding and excluding every file / folder that is generated by Android Studio / Gradle.
Windows File Indexing
Windows file indexing seems to also slow down Gradle builds. Turn off Windows File Indexing for the directories used by Gradle / Android Studio.
Here are my "Windows File Indexing" and "Windows Defender Process" exclusions :
C:\Program Files\Android\*
C:\Users\<yourUserAcct>\.android\*
C:\Users\<yourUserAcct>\.AndroidStudio3.0\*
C:\Users\<yourUserAcct>\.gradle\*
C:<pathToYourAndroidStudioProjectFolder>

In case setting -Xmx4096m -XX:MaxHeapSize=256m (and etc.. mentioned in above answers) doest work, then do this manually:
Step 1 : Start Android studio and close any open project (File > Close Project).
Step 2 : On Welcome window, Go to Configure > Settings.
Step 3 : Go to Build, Execution, Deployment > Compiler
Step 4 : Change Build process heap size (Mbytes) to 1024 and Additional build process to VM Options to -Xmx512m.
Step 5 : Close or Restart Android Studio.

This might sound stupid and off topic but in my case I was using an external 4k Monitor with my MacBook Pro 13' (MacOS High Sierra, 2016) and I had the resolution set to the wrong scaled resolution. Switching to another scaled resolution where there was no "using a scaled resolution may affect performance" warning resolved my overall performance issues. In my case I had to increase the resolution to max.
So for me it was an overall performance problem which first surfaced with Android Studio, it was not an Android Studio specific problem.
EDIT 25.11.2017
As a result I had to increase font sizes in Android Studio:
and on my Mac in General. I followed some of these tips to get that done.

Just for anyone looking, after upgrading to El Capitan, I noticed a huge lag with the IDE. After increasing a ton of RAM and using the suggestions above, it turned out that I needed to update the legacy Java, and reinstall via: https://support.apple.com/kb/DL1572?locale=en_US
After installing this, all lag was gone.

Well, one thing that worked for me is using physical android device instead of emulator. As in my PC( i5 and 4GB RAM ) the android studio takes about 700MB of memory and the emulator takes another 700. Thus the whole performance of the computer goes down. Working with a physical device saves the strain from the emulator.

DO NOT EDIT studio.vmoptions ,It may not work.
In gradle.properties file (in app directory) add this :
org.gradle.parallel=true
org.gradle.jvmargs=-Xmx7g -XX:MaxPermSize=1024m -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF-8

I followed this post and it worked great for me.
EDIT:
Following tips have been mentioned in the above post.
In gradle.properties, put this:
org.gradle.daemon=true
org.gradle.jvmargs=-Xmx2048m -XX:MaxPermSize=512m -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF-8
org.gradle.parallel=true
org.gradle.configureondemand=true
And in build.gradle, put this (Note this will disable lint check):
tasks.whenTaskAdded { task ->
if (task.name.equals("lint")) {
task.enabled = false
}
}

I just want to share my case:
if you need play-store library, don't compile all of it, just compile library that you need. example: if you only need maps library instead of compile 'com.google.android.gms:play-services:9.0.2' do this compile 'com.google.android.gms:play-services-maps:9.0.2' on your gradle
Dont use OpenJDK for the java, I use java 7 oracle and it works well. if yout need to change default java do this on linux terminal sudo update-alternatives --config java and pick the number
I'm using ubuntu 32bit 4GB RAM. that's all the issue I ever encounter with AS.

There are many ways to speed up Android Studio.
Speed up gradle build time.
1.Go to Project gradle.properties file and remove comment from both line.
2.copy gradle.properties file to your .gradle folder so that you don't need to setup for every project.
Enable Work Offline so that Android studio/Gradle don't need to check for newer file over internet every time.

I've quickly resolved this issue by upgrading gradle (Android Studio seems to use old version).
1) Download latest version (https://gradle.org/gradle-download/) and unpack somewhere.
2) Update path in Android Studio: File > Settings > Build, Ex../Gradle

This worked for me!
Open build.gradle (it's inside your project) and change the both jcenter to mavenCentral
(you can do it in Global file too: C:\Program Files\AndroidStudio\plugins\android\lib\templates\gradle-projects\NewAndroidProject\root\build.gradle.ftl however, you will need to do this modification again after AndroidStudio upgrade)

My Android Studio was not only slow in general use, but also when building.
Here's what I did:
Uninstalled Android Studio (Don't delete, uninstall it and check delete the SDK too). Then delete Android folders located in C:\Users\\ folder namely: .android, AndroidStudioX.X
Uninstall the SDKs via the SDK manager, remove everything ( If there is lef SDK folder, delete them )
Download and Reinstall the latest build for Android Studio (v2.1.2 as of this writing); Install only the SDK/Emulators you need;
It's fast now.
My Story before that:
My laptop sports an Intel Core i7-3612QM and 8gig of ram. When I builded, all the 4 cores/8 threads were on 100% usage. My entire system froze until the ~10 minute wass done. Gradle took me like ~10 unproductive minutes of slow down. This is very annoying. I am using Android Studio since 1.4. There were also tremendous slow down when I copy paste code to and from, selecting menus, right-click context menus, editing manifest, editing gradle files, opening layout files, rendering in the UI Editor, etc. Its was very unusable most of the time.
Due to frustration, I did the above steps. Its fast now. Very usable just as before. I build for only ~20 seconds compare to ~10minutes before that. Also, Android Studio eats about 6gig with emulator and browser with lots of tab open, unlike before its hovering on 98% RAM usage. Not just that, I even saved 45 gigs of space for whatever reason. I only use couple of SDKs and Emulators when I checked the Android SDK folder, it occupies 45gig of space! I think the IDE is having a hard time accessing/IO on my SDK folder.
If you've tried other given solutions and still experiencing the same issue, it may be time to remove Android IDE/SDKs altogether and start anew (it might take you sometime to setup that newly, but its worth it. Considering I've been suffering this sluggishness for months and cost me my productivity).
I really guess that this might be caused by cumulative patches that has been done since then. Or the 45 gig SDK folder on my poorly defragmented drive. I don't know and I could be wrong.
Thank you! HTH

I should mention that if you are using Mac, downloading and running an app from the App Store (like "iBoostUp" etc.) which will clean out unused system files can speed up your computer dramatically, including AS.
I also found that adding more memory to my Mac sped up AS as well.

I noticed that AS transfers too much data from/to HDD. It is very annoying, especially when starting to write a new line of code. So, I think, better will be reinstalling a hard disk with SSD. I have i5 with 6 Gb of memory, and the CPU seldom loads more than 50% even at build time. So, the most weak place is HDD.

Click Help > Edit Custom properties and add this line:
sun.java2d.noddraw=false
... worked successfully for me to fix the speed issues (Windows 10 64-bit). It's absolute voodoo as far as I'm concerned (I haven't done any research on why that should work), and there is a warning above that property that it can cause blinking and fail to repaint on some graphics cards, but there you go. (Inspired by LairdPleng's comment, further information)

1 The most common cause of slowness is using Emulator, especially more than one. USB debugging with the external mobile device can be used.
2 Invalidate caches every month or so
One Simple thing that no one has mentioned is File>Invalidate Caches.

Please add in setting.gradle (root folder)
startParameter.offline=true

I have tried to measure speed of Android Studio 3.1.4 on the same hardware: Macbook Pro 2011, RAM 4Gb, SSD 240GB Samsung, Core i5 2.4Ghz. I have installed on this machine 3 different OS: Windows 10, MacOS Hight Sierra 10.13, Ubuntu 18.04. Avarage build time (running command: gradlew clean build, gradlew clean assembleRelease) on MacOS/Ubuntu was around 30% faster than on Windows.
On my another working machine: Core i5 3.0 Ghz 7400, RAM 16Gb, SSD 250Gb. Build time takes 4.34min on Windows 10 machine. The same project on a little bit slower processor, but with the same RAM and SSD and it is running Ubuntu 16.04 build time takes two times faster!! Well I was shocked with results, but still I choose Windows as development machine, because it's much more comfortable for me to use comfortable and usable keyboard and sotfware than on Unix like systems. And even if I had to choose between MacOS and Ubuntu - mac is really much easier to setup everything, and Ubuntu is too complex to use for usual people. Choise is up to you.

Apart from following the optimizations mentioned in existing answers (not much helpful, was still painfully slow), doing below did the trick for me.
HP Notebook with 6 GM RAM and i5 processor I have, still android studio was terribly slow.
After checking task manager for memory usage, noticed that there is a software called "HP Touchpoint Analytics Client" that was taking more than 1 GB memory.
Found that it's a spyware installed by HP in Windows 10 after searching about it in Google.
Uninstalled a bunch of HP software which does nothing and slows down the system.
Now, Android studio is considerably fast - Gradle build completes in less than 30 seconds when compared to more than 2 minutes before. Every keystroke would take 5 seconds to respond, now it is real time and performance is comparable with Eclipse.
This might be true for Laptops from other vendors as well like Dell, etc.
HP really messed up the user experience with their spyware for Windows 10 users.
Uninstall them, it will help Android studio and improves the overall laptop experience as well.
Hope this helps someone. Thanks.

Balance memory consumption and build speed using gradle options. For sample
Android Studio 2022.1.1 (PC RAM 16GB)
Gradle v7.3.3 (./gradle/wrapper/gradle-wrapper.properties)
AGP v7.2.0 (./build.gradle)
com.android.tools.build:gradle:7.2.0
Cache Fix Gradle Plugin
org.gradle.android.cache-fix:org.gradle.android.cache-fix.gradle.plugin:2.5.3
This Google Services dependency version supports Gradle Configuration Cache
com.google.gms:google-services:4.3.5
./gradle.properties
android.enableJetifier=true
android.jetifier.ignorelist=bcprov-jdk15on
android.useAndroidX=true
kapt.incremental.apt=true
kapt.use.worker.api=true
kotlin.daemon.jvm.options=-Xms1g -Xmx4g
manifestmerger.enabled=true
org.gradle.caching=true
org.gradle.configureondemand=true
org.gradle.daemon=true
org.gradle.jvmargs=-XX:InitialHeapSize=1g -XX:MaxHeapSize=6g -XX:MaxPermSize=2g -XX:MaxMetaspaceSize=2g -XX:NewSize=1g -XX:MaxNewSize=2g -XX:+HeapDumpOnOutOfMemoryError -Dfile.encoding=UTF-8
org.gradle.parallel=true
org.gradle.unsafe.configuration-cache=true
org.gradle.unsafe.configuration-cache-problems=warn
Useful links:
https://proandroiddev.com/how-we-reduced-our-gradle-build-times-by-over-80-51f2b6d6b05b
https://developer.android.com/studio/build/profile-your-build#using-the-gradle---profile-option

Android Studio - How to increase Allocated Heap Size

I've been using Android Studio for 3 months now and one of the apps I started on it has become fairly large. The memory usage indicated at the bottom right of the program says my allocated heap is maxed at 494M.
When I start to change the XML files my memory usage quickly reaches that cap and the IDE crashes with an Out Of Memory error like this.
I've tried to increase the heap size using this but so far there has been no effect.
I've looked at dozens of articles and other questions on how to increase the heap size but none of their answers are working. No matter what I do to the VMOPTIONS or the IDE settings the heap size never increases. I believe I am editting the correct file for the VMOPTIONS because if I purposely give it an invalid command Android Studio complains about it and doesn't start.
I'm using windows 7 - 64 bit and have 16GB RAM.
Has anyone else had this problem with Android Studio? And were you able to fix it?

-------EDIT--------
Android Studio 2.0 and above, you can create/edit this file by accessing "Edit Custom VM Options" from the Help menu.
-------ORIGINAL ANSWER--------
Open file located at
/Applications/Android\ Studio.app/Contents/bin/studio.vmoptions
Change the content to
-Xms128m
-Xmx4096m
-XX:MaxPermSize=1024m
-XX:ReservedCodeCacheSize=200m
-XX:+UseCompressedOops
Xmx specifies the maximum memory allocation pool for a Java Virtual Machine (JVM), while Xms specifies the initial memory allocation pool. Your JVM will be started with Xms amount of memory and will be able to use a maximum of Xmx amount of memory.
Save the studio.vmoptions file and restart Android Studio.
Note:
If you changed the heap size for the IDE, you must restart Android Studio before the new memory settings are applied. (source)

I looked at my Environment Variables and had a System Variable called _JAVA_OPTIONS with the value -Xms256m -Xmx512m, after changing this to -Xms256m -Xmx1024m the max heap size increased accordingly.

Or, you can go to your android-studio\bin folder and change these -Xmx and -Xms values in studio.exe.vmoptions or studio64.exe.vmoptions files (depending on which version you are running).

You should not edit any files in the IDE installation directory. Instead, you can customize the attributes by creating your own .properties or .vmoptions files in the following directories. (This has been possible on some platforms before, but it required you to copy and change the entire contents of the files. With the latest changes these properties are now additive instead such that you can set just the attributes you care about, and the rest will use the defaults from the IDE installation).
Note: As of Android Studio 2.0, you can create/edit this file by accessing the "Edit Custom VM Options" file from the Help menu.
http://tools.android.com/tech-docs/configuration

I increased my memory following the next Google documentation:
http://tools.android.com/tech-docs/configuration
By default Android Studio is assigned a max of 750Mb, I changed to 2048Mb.
I tried what google described but for me the only thing that it worked was to use an environment variable. I will describe what I did:
First I created a directory that I called .AndroidStudioSettings,
mkdir .AndroidStudioSettings
Then I created a file called studio.vmoptions , and I put in that file the following content:
-Xms256m
-Xmx2048m
-XX:MaxPermSize=512m
-XX:ReservedCodeCacheSize=128m
-XX:+UseCompressedOops
Then I added the STUDIO_VM_OPTIONS environment variables in my .profile file:
export STUDIO_VM_OPTIONS=/Users/youruser/.AndroidStudioSettings/studio.vmoptions
Then I reload my .profile:
source ~/.profile
And finally I open Android Studio:
open /Applications/Android\ Studio.app
And now as you can see using the status bar , I have more than 2000 MB available for Android Studio:
You can customize your values according to your need in my case 2048Mb is enough.
UPDATE : Android Studio 2.0 let's you modify this file by accessing "Edit Custom VM Options" from the Help menu, just copy and paste the variables you might want to keep in order to increase it for everversion you might have on your box.

If you are using MAC BOOK, this option is available inside Applications -> Right click Android Studio then choose Show Package contents -> bin.
or
open -e /Applications/Android\ Studio.app/Contents/bin/studio.vmoptions
Then increase Xmx value
-Xms128m
-Xmx2048m
-XX:MaxPermSize=350m
-XX:ReservedCodeCacheSize=64m
-XX:+UseCodeCacheFlushing
-XX:+UseCompressedOops
Now your Android Studio will be super-fast.

Android Studio 3.1 has option to edit your customize virtual memory options.
You can go Android Studio > Help > Edit Custom VM Options
Then paste below settings code to studio64.exe.vmoptions file & Save it.
file location : "\Users\username\.AndroidStudio3.**\config\"
-Xms128m
-Xmx4096m
-XX:MaxPermSize=1024m
-XX:ReservedCodeCacheSize=200m
-XX:+UseCompressedOops

You can try any one of the following
1)Change the gradle.properties file and change the heap size as per your requirement.
If org.gradle.jvmargs=-Xmx2048M is not sufficient then change to 4096 as given
org.gradle.jvmargs=-Xmx4096M
2)"Edit Custom VM Options" from the Help menu.
It will open studio.vmoptions / studio64.exe.vmoptions file.
Change the content to
-Xms128m
-Xmx4096m
-XX:MaxPermSize=1024m
-XX:ReservedCodeCacheSize=200m
-XX:+UseCompressedOops
Save the the file and restart Android Studio.

Note: I now this is not the answer for the post, but maybe this will be helpful for some one that is looking.
If Nothing of this works for you, try on a Mac this to see if helps you, in the last version of Android Studio, the studio.vmoptions is inside the AndroidStudio.app in your Applications folder.
So right click or ctrl click on your AndroidStudio.App and then select show package content the studio.vmoptions is in:
Contents/bin/studio.vmoptions
Replace or change it and you will get all the RAM you need.
Regards.

I tried the _JAVA_OPTIONS thing but it wasn't working for me still.
In the end, what worked for me was the following:
Launching studio64.exe instead of the studio.exe(I've got a 64-bits machine).
Add/Change the following values in "studio64.exe.vmoptions":
-Xms2048m
-Xmx2048m
-XX:MaxPermSize=1024m
-XX:+CMSClassUnloadingEnabled
-XX:+CMSPermGenSweepingEnabled
-XX:+HeapDumpOnOutOfMemoryError
-Dfile.encoding=utf-8

There are a lot of answers that are now outdated. The desired way of changing the heap size for Android Studio recently changed.
Users should now create their own vmoptions file in one of the following directories;
Windows:
%USERPROFILE%\.{FOLDER_NAME}\studio64.exe.vmoptions
Mac:
~/Library/Preferences/{FOLDER_NAME}/studio.vmoptions
Linux:
~/.{FOLDER_NAME}/studio.vmoptions and/or ~/.{FOLDER_NAME}/studio64.vmoptions
The contents of the newly created *.vmoptions file should be:
-Xms128m
-Xmx750m
-XX:MaxPermSize=350m
-XX:ReservedCodeCacheSize=96m
-XX:+UseCompressedOops
To increase the RAM allotment change -XmX750m to another value.
Full instructions can be found here:
http://tools.android.com/tech-docs/configuration

First check how much memory allocated for your android studio
to check that follow this steps :
File -> Settings->Appearance & Behavior->Appearance
then check the show memory indicator option like below image red highlighted part
In my case my RAM is 12Gb so i have allocated memory for android studio 6gb .To edit that follow this steps
Help->Edit custom VM options
-Xmx6g
In my case, i have set it 6gb because my pc ram is 12 GB. Its upto you how much memory you want to allocate to your android studio

This is how you change the heap size currently in Android Studio 3.6.1
On Windows in your Android Studio:
Select File -> Settings (the popup below will be displayed)
Select Appearance & Behavior
Select System Settings
Select Memory Settings
Then change the IDE Heap Size settings to your desired value
On Mac:
Select Android Studio
Select Preferences
The same pop up will appear. However, this time on the Mac its called Preferences.
Follow the same steps as the Windows version of Android Studio to adjust the heap size wants the Preferences dialog has been displayed

On Mac OSX one can easily change heap size by going to first menu item, Android Studio > preference > System Settings (left menu) > Memory Settings and change heap size there in the dialog.

On Windows 7, the configuration files at [INSTALL-LOCATION]\bin seem to be ignored. Per the following Google documentation, the file to be modified should be here: %USERPROFILE%\.AndroidStudio\studio[64].exe.vmoptions
http://tools.android.com/tech-docs/configuration
Odd that there is no such file upon a clean install of Android Studio 1.1 from the developer site. And they are in the old (ignored) location. Once I copy the file (studio.exe.vmoptions in my case) over and modify it, the change is respected.
However, the fun doesn't stop there. There's an upper value for -Xmx which may be related to the amount of memory in your system. I just bumped my machine's memory from 4Gb to 16Gb, and assumed I could set -Xmx to 2048m, but I found that if I set it to anything larger than 1500m, Android Studio would silently fail to launch with no indication at all as to why. I have more RAM on the way, so it will be interesting to see if I can increase the value at that point.
I hope this additional information is helpful. While all of the above replies were undoubtedly true at one point (and may still be in some environments), I found that this was the only approach that increased the memory used by AS for me.

Open studio.vmoptions and change JVM options
studio.vmoptions locates at /Applications/Android\ Studio.app/bin/studio.vmoptions (Mac OS). In my machine, it looks like
-Xms128m
-Xmx800m
-XX:MaxPermSize=350m
-XX:ReservedCodeCacheSize=64m
-XX:+UseCodeCacheFlushing
-XX:+UseCompressedOops
Change to
-Xms256m
-Xmx1024m
-XX:MaxPermSize=350m
-XX:ReservedCodeCacheSize=64m
-XX:+UseCodeCacheFlushing
-XX:+UseCompressedOops
And restart Android Studio
See more Android Studio website

I found on on Windows 7/8 (64-bit), as of Android Studio 1.1.0:
[INSTALL_DIR]\bin\studio64.exe.vmoptions be used (if it exists), otherwise it would always fall back to %USERPROFILE%.\AndroidStudio\studio[64].exe.vmoptions
If you want the settings managed from %USERPROFILE%.\AndroidStudio\studio[64].exe.vmoptions, just delete the one in the installation directory.

Go in the Gradle Scripts -> local.properties and paste this
`org.gradle.jvmargs=-XX\:MaxHeapSize\=512m -Xmx512m`
, if you want to change it to 512. Hope it works !

you are not supposed to modify the bin/studio.exe.vmoptions file, which will be verified during applying update patch.
Solutions are here http://tools.android.com/tech-docs/configuration
copy that file into following location, then change the -Xmx1280m to whatever you want.
Windows:
%USERPROFILE%\.{FOLDER_NAME}\studio.exe.vmoptions
and/or
%USERPROFILE%\.{FOLDER_NAME}\studio64.exe.vmoptions
%USERPROFILE%\.{FOLDER_NAME}\idea.properties
Mac:
~/Library/Preferences/{FOLDER_NAME}/studio.vmoptions
~/Library/Preferences/{FOLDER_NAME}/idea.properties
Linux:
~/.{FOLDER_NAME}/studio.vmoptions
and/or
~/.{FOLDER_NAME}/studio64.vmoptions
~/.{FOLDER_NAME}/idea.properties

Had this Xms and Xmx memory low issue happen to me any time I was working with the XML. I also tried increasing this memory, only to find that it just took a little longer for it to happen again.
After getting very frustrated and almost deciding to convert all my current projects back over to Eclipse, which I did not want to do, I figured out what was causing it and was able to repeat this failure and prevent it every time.
While editing the XML in (Text view), and using the "Preview" render view, this causes the loss of memory, every time. Turning off "Preview" and using the Design tab to render the screen only, I am able to use Android Studio all day long, with no crash.
I wish this could be fixed for good, because it would be very nice to use the "Preview" render while editing the XML, however I am glad I can keep using Android Studio.

On Ubuntu, it's straight forward, clicking Help > Edit Custom VM Options
. The IDE asks whether to create for you a file, click OK.
An empty studio64.vmoptions file is create and paste the following variables:
-Xms128m
-Xmx4096m
-XX:MaxPermSize=1024m
-XX:ReservedCodeCacheSize=200m
-XX:+UseCompressedOops
Restart the IDE, the Max Heap Size is increased to: 4,062M

May help someone that get this problem:
I edit studio64.exe.vmoptions file, but failed to save.
So I opened this file with Notepad++ in Run as Administrator mode and then saved successfully.

IF by changing or creating the .studio.exe.vmoptions doesn't work, then try changing the gradle.properties file and change the heap size as per your requirement.
It really worked for me on my Windows 7 with 4Gb RAM and Android Studio 2.2 install on it.
Working properly with no error and displaying 'Gradle Sync complete'

-Xms256m
-Xmx2048m
-XX:MaxPermSize=512m
-XX:ReservedCodeCacheSize=128m
-XX:+UseCompressedOops

As of 2022, you may check this link here.
https://developer.android.com/studio/intro/studio-config.html
Windows
Syntax: %APPDATA%\Google\<product><version>
Example: C:\Users\YourUserName\AppData\Roaming\Google\AndroidStudio4.1
macOS
Syntax: ~/Library/Application Support/Google/<product><version>
Example: ~/Library/Application Support/Google/AndroidStudio4.1

Develop Reference

The Android operating system is a mobile operating system that was developed by Google (GOOGL?) to be primarily used for touchscreen devices, cell phones, and tablets.