PHPStorm constantly use 10+% CPU and 650MB+ RAM and a constant disk transfer of 12 MB/s - is this normal?

I recently bought the paid version and I have one concern.
When minimized I see a green progress bar on the PHPstorm icon, moving extremely slowly... The active project contains many 1000s of files and 100.000+ images...
I assume it's indexing all files in the project, but I don't want this... it should skip the whole "images" directory.

Please help.