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 had similar issues with a very slow start and heap issues, increasing VM did not make a huge difference, just delayed the inevitable, the fix for me was to invalidate the cache via File > InvalidateCaches/Restart.

https://www.jetbrains.com/help/idea/2016.1/cleaning-system-cache.html