My GTX 580 started under performing after I put it my Corsair AX 750.
I get very, very low FPS.
Under 40fps in max graphics in Assassin's creed.
Frequent low fps spikes in BC2, max 80 for a few seconds.
Used to get like at least 100 a lot.
Pretty much everything that requires some resource out of my GTX 580 is like that.
I'm gonna try replacing the pcie power cables.

@Alen
@iverson954360
@Doc

Suggestions on what to do and do you know why it happened?