You can override the default vmoptions with your own personal settings by choosing Help > Edit Custom VM Options from the Android Studio toolbar. This will create a local copy which you are free to edit.

Alternatively, you can edit the default vmoptions directly using the paths given below. Note that this method is not recommended, and your changes may be overwritten when updating Android Studio.

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 
~/.{FOLDER_NAME}/studio64.vmoptions
~/.{FOLDER_NAME}/idea.properties

Default setting for Android Studio 64-bit

-Xms128m
-Xmx750m
-XX:MaxPermSize=350m
-XX:ReservedCodeCacheSize=96m
-ea
-Dsun.io.useCanonCaches=false
-Djava.net.preferIPv4Stack=true
-Djna.nosys=true
-Djna.boot.library.path=

-Djna.debug_load=true
-Djna.debug_load.jna=true
-Djsse.enableSNIExtension=false
-XX:+UseCodeCacheFlushing
-XX:+UseConcMarkSweepGC
-XX:SoftRefLRUPolicyMSPerMB=50
-Didea.platform.prefix=AndroidStudio
-Didea.paths.selector=AndroidStudio

Optimized Setting

-Xms1024m
-Xmx4096m
-XX:MaxPermSize=1024m
-XX:ReservedCodeCacheSize=256m
-ea
-Dsun.io.useCanonCaches=false
-Djava.net.preferIPv4Stack=true
-Djna.nosys=true
-Djna.boot.library.path=

-Djna.debug_load=true
-Djna.debug_load.jna=true
-Djsse.enableSNIExtension=false
-XX:+UseCodeCacheFlushing
-XX:+UseConcMarkSweepGC
-XX:SoftRefLRUPolicyMSPerMB=50
-Didea.platform.prefix=AndroidStudio
-Didea.paths.selector=AndroidStudio