I've had several instances where RubyMine sucks up 100% CPU.
It doesn't happen all the time, but when it happens, it doesn't seem to be doing anything visible (indexing or something like that), and the editor really becomes unusable, (ie, type a letter, takes 2-3 seconds to show up on the screen).
I tried do what this document said to:
However, when I make the change in the startup script to enable the CPU and Memory snapshot tool...it crashes when I try to start rubymine. I take out the change that the document recommends and it is fine.
I'm using the Beta 2 version 2 rubymine on Mac OS X Leopard.