I'd try another card as suggested by Bob, if the BIOS and motherboard drivers don't help.
Im using the XFX R7800 series (ghost). After I game for about 30 minutes, both of my monitor screens turn into colored vertical lines. But its not consistent, sometimes it'll do that after about 3 matches of league of legends. Ive done research and I cant find a solid answer. Ive tried to see if its a RAM problem, or memory issue, but I dont think it is. Im guessing it could be my VGA cables? I cant pin point it. I dont think its a temperature issue either. Where should both of my VGA cables be plugged in? They're plugged in directly from the graphics card, to the monitors. Other than that, everything else runes fine.