No, 2 6950's will want like a 750+ watt psu,but there is no need unless you want 3+ monitors, the 6950 can be unlocked to basically a 6970, throw in a little overcllock and you just created a card worth a pretty penny more than you spent, but it hould be able to smash anything out for a little while already, ne need for more than that and you'll need a new psu and stuff anyways and need to make sure your mobo can actually perform crossfire properly, as in a x16 and x8 or 2 x8's when 2 are plugged in or something like that, not a x16 and x4.