If you want to objectively, accurately and scientifically determine what PSU power is required for your Vid card and PC in both watts and 12v rail amps., the forum Utility link below will show you how easy it is to calculate this information and objectively determine which PSUs are quality built, reliable PSUs that can meet your needs. Be advised that the available 12v rail amps. is just as important as the total PSU wattage. You need both to be correct.
It's a Corsair 620 HX. It says it has 3 12v rails with 50 amps combined so i think it will be sweet, however It looks like the 2 cards will be way too close to each other if i had them in xfire so I'll probably only use one, therefore making my original question redundant.