Corsair CS750M PSU came with a PCI-E splitter cable with 2 6+2 pin plugs at 1 end and an 8 pin plug at the other. Graphics card (Asus GTX970) has only 1 8 pin port. Can I use the cable that came with the PSU, connect 1 6+2 plug into the graphics card and just leave the other unconnected/dangling or do I have to buy a new cable? I'm new to this and appreciate any advice you might have.