So I have a prebuilt machine (yes I know) that was set up for SLI with 2 8/6 pin cables. Basically coming out of my PSU for video card power I have 2 of these (identical):
http://imgur.com/TMZSV
The card I have in there now is a 580, which requires an 8 pin and a 6 pin. I'm getting a 690 which requires 2 8 pins. I'm wondering if I can take each 8 pin from the 2 separate cables and use them for the 690 and just leave the 6 pins hanging. I know wattage won't be a problem.