Game is randomly dropping frames

I recently bought a new pc with perfect specs ( GTX 960 2g. i5 6600 3.30gz ) and i got 300fps on csgo on the highest settings i got a nice 200.0 fps on crossfire but its dropping around 30frames every 5/10 seconds which is causing a quick screen freeze and thats really annoying because i cant aim with it... some people say that the game is not running very well on newer hardware but i highly doubt it because i know people with new specs that barely got lag...