Looking to add a more powerful PS to my system, I found as I added HD's and DVD burners I had problems restarting. Using a P5K MB kept getting a 'overclocking failed' even when not o/c. So I disconnected the extra HD's and DVD burner and it boots fine.Want to get a new PS but the watt math does not add up?Example: The OCZ 600W has 4 12V rails @ 18A yet the Corsair 620W as 3 rails @18A yet rates higher?OCZ GameXStream 600W shows:Output:+3.3V: 36A+5V: 30A+12V1: 18A+12V2: 18A+12V3: 18A+12V4: 18ATotal Output: 600Wand the Corsair HX620 shows:Voltage / Max. Current+3.3V: 24A+5V: 30A+12V1: 18A+12V2: 18A+12V3: 18A-12V: 0.8A / 9.6W+5Vsb: 3A / 15W+3.3V, +5V Combined: 170W+12V Combined: 600WTotal Power: 620W

According to OCX, the max combined power on the 12v rails is 580 watt, but at that level you would get no output on the 3.3 or 5 v. According to Corsair, you can get a max of 600w on 12v. Assume the same case of no output on 3.3 or 5 v at that level. So you would have to determine the max simultaneous load required at all voltages to compute total wattage requirement. scott s..

I went with the Corsair, after reading their support forum. It seems fine, quiet, does generate warm airflow.