Your power supply should have a 6+2 PCI-E cable. Use that to connect to the graphics card. If your power supply does not have that cable, then I'd probably be looking at replacing it with a quality unit that does.
Your power supply should have a 6+2 PCI-E cable. Use that to connect to the graphics card. If your power supply does not have that cable, then I'd probably be looking at replacing it with a quality unit that does.