Uber 0 FPS spikes

[skpok]

I've been playing in a private server for like a week and yesterday when i was about to play some more i started having huge low FPS spikes... it happens like this: i'm playing and when i press the mouse or keyboard, my fps goes to 0 and 3 seconds later it goes back to 45+ and when i press again it lags again... I already tested Cabal Brasil and it didnt have any lag spikes.... Does any1 know how can i solve this problem?

Thank you.