So am planning to upgrade from my GTX 660 to a GTX 960 2GB, but i would like to go for either gtx 960 4GB or even a 970 but they require a 8 pin connector witch my psu doesn't have and i can't afford to upgrade it (my psu is a telsa atx 750W silent running) is there anything i can do other then upgrading my PSU or should i just stick to the 2GB 960?