I don't think it's unreasonable to go to 700W. I'm running one right now with a Phenom 955 BE, Radeon 5770, 2 HDD, 5 120mm fans, 2 sticks of DDR3 RAM, and a DVD/CD-RW combo drive. Now the 4850 can draw up to 250W at peak load and the i5 draws 120W at peak. That's 370 already and we haven't touched the other parts yet. So…