http://hardocp.com/article/2010/11/...deo_card_review
"The Thermal Design Power (TDP) of the GeForce GTX 580 is 244 Watts. At idle it is 37 Watts. This compares to the GeForce GTX 480 TDP of 250 Watts. Already we can see that this video card should be slightly under the GTX 480 Wattage, with better performance. You will still need 1x 6-pin and 1x 8-pin power connectors to run this video card. The recommended power supply is 600 Watts. Our Fermi PSU Guide still should come in very handy for Fermi "enthusiasts.""