will an ATRIX Model 500T psu rated at 650w power an 8800GTX card?

Answer 1

any p.s.u rated over 600w should power a single 8800gtx card,however its normally best to refer to the cards documents and manuals,as this should have recommended p.s.u,s and were to get them from
however try looking at this and see if it helps http://www.gpureview.com/show_card.php?card1=474

Answer 2

a lot depends on what else you are powering but 650 watt should handle whatever you throw at it.
i am using a 450 watt with 2 pci-e 128meg nvidias in an SLI combo, 3 roms, 2 hard drives lots of custom lights etc