Just installed an HD 7870, I get good FPS in games, but every 5seconds

[RufioStill]

something stops for one second, like it's not fluid for 1 second every 5 seconds. I tried CS:GO and Path Of Exile so far both maxed out I get 60FPS (they don't drop and I experienced this on both games) which I consider good enough, but why is this happening? It gets really annoying, I have the latest drivers and I just installed the card an hour ago..

Perhaps the drivers? O do I need to tweak something?

Thanks

EDIT: Also tried closing processes without any results. Could it be that NVIDIA drivers are still installed?

 

[RufioStill]

Already fixed it It was a software running on the background called Flu.x which changes the brightness of the screen. I really like how games look with Flu.x on but I guess I won't be able to play with it.