Well i finally got up the money to get a new motherboard and bought a 2nd 4850. Everything boot's up fine and i can some games like Guitar Hero 3, Second Life, Perfect World, TF2 ect.. But when i launch COD4 i can play for about 2 minutes in single player mode then the whole pc insta shuts down. I can boot back up fine and launch it again. I watched the voltage on the +12 -12 , and 5v rails and it always stays within safe range. I'm kind of unsure of what is causing the PC to crash like that. Specs AMD Phenom 9850 @ stock 2 Sapphire 4850's @ stock 2 80gig Satadrives in RAID 0 1 750gig Sata drive 3 2 Dvdburners and a CD burner 5 120mm Fans 1 220mm fan. 585w HEC Orion PSU Any help on what might be the problem would be great.