Why is IntelliJ 13 IDEA so slow after upgrading from version 12?

Question

While using IntelliJ 13 ultimate edition for a week, it just seems really slow.

First of all, the whole IDE stops for a second or so every once in a while. The Java

Answer 1

I have solved my performance issues by switching to the 32 bit mode. It seems to be related with the JRE that IntelliJ runs with. It ships with a 32 bit 1.7 JRE which is used when starting idea.exe. If you start idea64.exe, it uses a 64 bit JRE installed on the system. In my case this was a 1.6 JDK (the one I use for development). This caused IntelliJ to be nearly unusable.

After installing a proper 64 bit 1.7 JDK everything was fine with the 64 bit mode, too.

See the answer on the IntelliJ Support web site.