axlrose :
Yeah tried messing around with gpu's. I took out my two 560 ti's and am currently running just one gtx 280 with no change. I thought my parts were in my signature, but you are the second post to ask for them, so perhaps they aren't showing like I think they are. Motherboard is an old evga 790i ultra. I have a gtx 280 ftw plugged in right now but only because I took my two 560 ti's out to see if that would help. Can't find any overheating in my gpu's with gpu-z or the new futuremark. I don't think it's them, though they'd be under warranty still if it were. PSU is a 1000W Zalman that I have been using in the system since I put this build together in 2008 some time. It ran until about a year and a half ago with the single gtx 280 and basically the same components. A year and a half ago I moved to the two 2gb 560 ti's when BF3 was released.
Didnt even notice your signature. Sorry
Try using just 1 of your 560ti's at a time
Plug one in, and do whatever it is that makes it glitch out. If it glitches, put the other in and do the same thing.
See if one of them is having problems.
If they both work individually maybe there is some SLI bridge problem or something?
Im not a computer expert by any means, but im trying to help the best i can!!