if you have troubles like me in idea because of heap sizes etc. open ( for mac users of course 😉 )
/Applications/IntelliJ IDEA 9.0.1.app/Contents/Info.plist
and in the lower part of the document you will see
change it as you wish, mine is :
<string>-Xms256m -Xmx1024m -XX:MaxPermSize=768m -ea -Xbootclasspath/a:../lib/boot.jar</string>
and I am happy with it :).