200W at max load. More if o/c'ed and double when SLI'ed. Figure 400W to be safe, ya' never max load like Furmark, that's 34W total power consumption for the video alone. A good 750W PSU should do it. Get one with 4 ea. 6+2 pin plugs and at least Bronze certified. With the $$$ you're already talking about damn sure don't skimp on a PSU.