So, I'm building my system, and my power supply, a Corsair 850x, comes with a pcie cable with an 8pin that goes into the power supply and then 2 6+2pins for connecting to the graphics card. I'm using a single EVGA GTX 980 SC ACX 2.0, which requires 2 6 pins. Can I just use the one 8pin cable to connect both six pins to the graphics card, or will I need to use a second cable as well to get enough power to the graphics card? Any help would be appreciated.