[BUG]Low GPU usage

Hey'all,

I've been experiencing some random low GPU usage. I can expend a couple hours 60+ fps, exit the game, come back 5 minutes later just to get 25fps and 80% of my GPU being used (according to MSI Afterburner).

I have a R9 390X, 8Gb RAM and a i7 2600K.

Halp :(