im considerin upgrading to the BFG GeForce 9800 GX2 or sli 8800gtx either way its goin to cost me the same, for me to upgrade to sli 8800gtx i would have to buy a £150psu from dell and another 8800gtx, would it make more sense to buy the 9800gx2 for the same price ? my current psu is 750w with 2 6 pin connectors can i upgrade to this card with my psu