I just replaced my Nvidea 640 card that came with my Alienware X51 with the EVGA 750 FTW. I have the R1 computer but the extra power requirements have not been a problem using Windows 7 and direct X 11. Played online Counter Strike using the EVGA Precision X OC tool and with just adding 51 MHZ I was hitting over 1400 MHZ with a stock motherboard, i3 (3220) and just 8GB DDR3 memory. Thanks EVGA you solved the problem with upgrading the X51 and using less power then the GTX 660.