Low 99% FPS

Hi,
In the last few weeks I have been playing and every few matches I get very low 99% FPS. Like 15-20 FPS. Normally my 99% is 60 FPS. I lowered my graphics settings and I am reinstalling the game right now. Does anybody have any experience with this? It only stared last week.

Thanks!

Update: I reinstalled it and its still there. 1st and 2nd game are ok then the 3rd and on is bad.

Another update for those watching: I reinstalled my graphics drivers and I think its fixed!