I've been having a lot of trouble with pixelation and also in-game display driver crashes. At first I thought the problem may have been my graphics card (Sapphire 5750) but I have RMA'd it three times and I'm still having trouble. So what I think it might be is my PSU, its 650Watt but its made by Azza so it was cheap and not made by a necessarily good company. Or maybe it could be the CPU (AMD Phenom Black Edition 3.4Ghz) It runs hot (60C) but it passes Everest's test. Someone told me it could be the memory (8GB DDR3) but I don't really see how RAM has anything to do with my problem. So what are some of you suggestions? 

Here is a video a made awhile ago of what is happening. <http://www.metacafe.com/watch/4392213/ati_radeon_5750/>

That was just a stress test most games tend to just freeze and crash or lock my system up.