How to speed up IntelliJ IDEA?

Question

IntelliJ IDEA

IntelliJ IDEA version 14.1.5 began to slow down.
Before such problems were not, everything worked quickly.
I did not install new plugins and did not update the existing ones.
The machine is powerful (i7, 16GB of RAM, ssd hard drive with 100 gigs free).
Operating system windows8.1 (reboot does not help).
How to determine what could be the problem and how to fix it?

Answer 1

Try to check the folder "C:\Users\Username\.IntelliJIdea14"
In the process of work, I accumulated data from various old projects there, everything was very slow until I cleaned it.