The 8 pin connector is a CPU 12V connector. It should NOT be used on a graphic card. The graphic card connectors on this Enermax PSU are two RED 6-pin connectors. Your ATi 3870X2 GPU comes with a 6-pin connector and an 8-pin connector. However only two 2x3 (6-pin) auxiliary power connectors are required to make this card work. You do not need an 8-pin (2x4) GPU connector for normal operation of this video card. The card should have come with an adapter that turns one of the Enermax' red 6-pin connectors into an 8-pin connector. If it doesn't have one, here is a tip on how you can rig up a connection yourself. If you wish to overclock though, you must connect a 'true' 8-pin GPU connector in order to get Overdrive to show up in Catalyst Control Center.