I've played two games with my new system and in both I encounter similar problems. After some time playing they start to show graphics glitches, white dots flashing, edge of textures white and grainy before the whole thing minimises. I can't maximise it again. With one of the games I can partially solve the problem, in arma 2 I can bring up some invisible menu type in "flush" and it works fine again. It was suggested it had something to do with the vram being full, "flushing" seems to help.
The gtx 580 is evga "superclocked" with 1.5 gb of memory. I use a 1920x1200 resolution and this is at very high settings. I tried turning off AA with deus ex but it didn't seem to help the problem. Is it possible that I'm running out of vram already? my psu is a corsair with 1000v or whatever so I wouldn't think it was that, is there a way of increasing the voltage manually? I tried a short test to look for overheating but it only got to the mid 60's I might try a longer test later.
It sounds like you are getting artifacts. this could be caused by an unstable overclock or to much heat. can you manually set you video card fan to 100% and see if this resolves the issue. if not try changing the clock settings back to stock. i know that you card came OC from factory but i have heard of some of these GTX 580OC not being entirely stable.
Well, there shouldn't be a problem there then. No other card you can borrow and try from a friend ? Or trying this one in an other sysytem ?
Maybe try to increase the GPU core voltage just a litlle bit maybe ?