First of all consider changing idea.vmoptions. idea.vmoptions is a text file with a list of JVM settings, it’s usually found in the bin folder in the Idea installation folder. This file can be open in any text editor. The following settings increase performance drastically on Sun JVM 1.6: -server -Xms128m -Xmx512m -XX:MaxPermSize=250m -XX:ReservedCodeCacheSize=64m -XX:+UseConcMarkSweepGC -XX:+AggressiveOpts [...]