My existing VX550w would appear to be OK for two 4850 graphics cards in Xfire mode judging by the total system power demand under load reported here http://www.anandtech.com/video/showdoc.aspx?i=3338&p=5 as 335.7 watts. The VX550w has a 12v rail of 41 amps.
However it also says in the body of the report thatNow I certainly don't expect a comment on a competitors power supply but that unit is supposed to have a single 12v rail of 80 amps.With two 4850s paired up in CrossFire, we once again ran into issues with our power supply. Our 1000W OCZ EliteXStream wasn't always enough for the dual-GPU setup and in Call of Duty 4 our system rebooted in the middle of our test at 2560 x 1600
Is there any obvious reason why my present unit wouldn't be adequate.