I would probably get the XXX version just because it is already clocked at the higher speed and since you are not going to volt mod. You could get the vanilla one and clock it up, but there is no guarranty that you will get there. As far as the frame rates I am not sure about the munbers, but I read one review where they said that the EVGA 7900gt super clock is faster than the x1800xt 512 (in most games in that review) and the 7800gtx(non 512). I am not trying to start a war here, but this is just what I read.