The Sapphire Nitro RX 580 needs an 8 pin and 6 pin I have both but my 8 pin is 4+4 pin and the 4 pin is what I use for my CPU. That leaves me with a 6 pin and a 4 pin. I have a 650W PSU Golden Field S728. Could I just use the 6 pin or do I have to buy a 6 pin to 8 pin adapter?