My friend wants to sell his GTX 480 to me for $150, so I thought it would be a good upgrade to add another GTX 480 to my system. I have a Seasonic M12D 850Watt powersupply. Wondering if that will handle the GTX 480 Sli? I found this review (http://www.geeks3d.com/20100414/power-consumption-of-two-gtx-480-in-sli-with-furmark-and-3dmark03/), and it said the power consumption under furmark is 624W. Is that the whole system power consumption or is it just the graphic cards? Please let me know. Thanks in advance.