Had problems also, for the first month or so not one issue then windows updated and i had problems left and right. I have an asus p7p55d pro i5 750 and a sapphire 5770. can't play games at all system crashes with gray lines. (can play for about 2 to 5 mins then it crashes.) emailed sapphire they sent me a bios update for my video card still had problems but crashes were now windows blue screen memory errors (memory dump) then i updated my mother board to the newest bios and got the latest chipset driver. problem seems to be fix played bioshock 2 and left 4 dead 2 all day not one crash.
I researched this problem for months before I got it to work I almost rma the card back to sapphire
I'm using cat 10.3 drives also plan to test my system for the next week to see if i can get it to crash