shit fps probs blargh

allright, since i reinstalled i have completely random fps lags from 10/15 to 75/125 ( tried multiple settings) most of the times its there, and sometimes i try to play and it works for hours untill i close ET and retry.

No weird processes that are running on my pc, checked that
Reinstalled ET, seemed to work, but then it was back 2nd time i played ET

Dont tell me this random shit lag is PB? :x