Sudden framedrops and stutters. FPS meter shows 60+, but it's not smooth, it feels like 20-30fps. When I play on Windows, the same 60+ fps are real, gameplay is smooth, no lags, no stutters.

Also on Linux, if you close galaxy\system map with "ESC", you get drop to 4-5 fps for no reason. If you open map againg and exit by ingame UI button, you get your 60+ fps back, but still stuttered as hell.