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Mac: running in 32-bit mode to lower memory usage


Created on: Jan 30, 2011 4:42 PM by Serge Baranov - Last Modified:  Jan 30, 2011 9:11 PM by Serge Baranov

By default, IntelliJ IDEA runs in 64-bit mode under Mac OS X. You may want to strip it down to run in 32-bit mode by the following:


  • open "Get Info" panel on your IntelliJ IDEA



  • check "Open in 32-bit mode" check box



Running IntelliJ IDEA in 32-bit mode may lower your memory consumption.

Tags: memory, mac, heap, 32-bit
Average User Rating
(1 rating)

Vladimir Krivosheev Vladimir Krivosheev  says:

Do not show warning about it if my vm options like "-Xms512m -Xmx2048m -XX:MaxPermSize=512m"

Dirk Jäckel Dirk Jäckel  says:

Activity Monitor says IDEA is using 370MB instead of 520MB.


What`s the drawback?


It seems the upper memory limit is 2GB then.

Serge Baranov Serge Baranov  says in response to Dirk Jäckel:

If your projects work fine with such heap, then you save memory by using 32-bit JVM. If you need higher heap for some reason, use 64-bit mode.

Valentin Schitov Valentin Schitov  says:

What are benefits of using PHPStorm 64-bit mode on MacOS X in comparison with 32-bit mode?

Serge Baranov Serge Baranov  says in response to Valentin Schitov:

The only benefit is that you can use larger maximum heap size. It may be useful if you have a lot of large projects open at the same time, but most users don't need it.

Andy Fyfe Andy Fyfe  says:

The community edition specifies -XX:+UseCompressedOOPS in the Info.plist file -- it should be -XX:+UseCompressedOops -- so it's a no-op.  The ultimate edition skips the option all together.


Compressing oops is supposed to reduce memory use.  Does it cause other problems?

Michael Hirsch Michael Hirsch  says in response to Andy Fyfe:

I've never had a problem with it.  I use it with Ultimate  with no problems and reduced memory.

Paul O'Keeffe Paul O'Keeffe  says:

Why not just make 32-bit the default? Needing a heap > 2G is fairly unusual for a Ruby project.


Its annoying to get the optimisation hint every time I start up.

Guido Gloor Guido Gloor  says:

I do get that warning all the time, too, and I do have plenty of RAM and want to run in 64 bit even if I waste memory like that.


Is it possible to just remove the warning message without adding explicit memory usage starting parameters?

Serge Baranov Serge Baranov  says in response to Paul O'Keeffe:

If you get it every time, it's a bug which will be fixed in the future update.

Guido Gloor Guido Gloor  says in response to Serge Baranov:

Good to hear, thanks

David Quinn-Jacobs David Quinn-Jacobs  says:

I don't get it.  I keep getting the message in PhpStorm since I upgraded to 2.0, and I am directed here.  I can't find an app called IntelliJ IDEA anywhere on my Mac, although I believe PhpStorm is a variant of it -- yet I can't locate an equivalent setting in PhpStorm.  So I continue to get the annoying message.

Serge Baranov Serge Baranov  says in response to David Quinn-Jacobs:

You should get the same option for PhpStorm, reappearing message is a bug which will be addressed in the next update.

David Quinn-Jacobs David Quinn-Jacobs  says in response to Serge Baranov:

I see now.  It's an option from the Finder, not within IDEA and/or PhpStorm.


Brian Morearty Brian Morearty  says:

When I run in 32-bit and choose File > Create Command Line Launcher and then launch it with "mine", it launches as 64-bit.


How can I make the cmd-line launcher run in 32-bit?



timo b timo b  says:

i have the phpstorm 2.01 now and i still see the message bubbling up under Snow Leopard...i marked "run in 32-bit-mode" within App icon of PhpStorm..but i am not sure, i think its not taking effect at all as it runs slow...

any new suggestions?

thank you


Jason Marshall Jason Marshall  says:

This may no longer be true.


Current JDKs turn on Compressed OOP handling by default, which uses 32 bit object pointers whenever memory usage is below 20-some gigabytes, which is most of us most of the time.


Supposedly the latest OS X JDK also includes this feature.

timo b timo b  says:

hmm ok now i see the option-checkbox remains checked on mac os x...but i am not sure if 32-bit works? how can i test it or see it? any terminal instructions for processes or such? thanx!

Deryl Doucette Deryl Doucette  says:

oh screw a bunch of RubyMine. GROSSLY overweight, slow, screws up left and right when installing gems, doesn't understand before_filter syntax correctly, constantly 'loses' Project directory structure, and just an overall PITA to use. oh and lets not forget that RubyMine 3.2.2 has serious issues with RVM. (Sucker was using rbx-head SDK rather than 1.9.2-p290 in a 1.9.2-p290 based project defined in .rvmrc when my default ruby is NOT even rbx-head), and it constantly posts a message about how 32-bit mode will reduce memory and gives you no way to stop that message from coming up on each and every startup UNLESS you're in 32-bit mode (which this thread is about). Piss poor program if you ask me.


DEFINITELY going back to just plain old TextMate! I've been following this editor since it was first released, and I have to say, I'm extremely disappointed with it. If I *had* to choose between IDEs to use, I would most definitely use Aptana Studio 3 over RubyMine 3.2.2.


Dennis Ushakov Dennis Ushakov  says in response to Deryl Doucette:

Deryl, I would suggest you reporting your problems at our bugtracker, so they can be fixed in future versions. Most of the problems you're reporting are considered fixed in 3.2.2, so please do provide some details

Deryl Doucette Deryl Doucette  says in response to Dennis Ushakov:

This is *in* 3.2.2. I just downloaded it about an hour ago and ran all this. However, when I get a chance (maybe later today) I'll read through the bug list so as not to duplicate and file what I have.

Dennis Ushakov Dennis Ushakov  says in response to Deryl Doucette:

Deryl, you can write to me at so we can discuss your problems without hijacking this thread.

Deryl Doucette Deryl Doucette  says in response to Dennis Ushakov:

Sure, my apologies for the thread hijack.

tfennelly tfennelly  says:

Where exactly is this "Open in 32-bit mode" checkbox option on the .app file info?  I don't see it:


Chris Custine Chris Custine  says in response to tfennelly:

The screenshot above is from Path Finder from Cocoatech, the 32-bit option will only show up using the built in Mac OSX Finder.