I am in the process of building a computer with a GTX 770. The 770 needs an 8 pin and 6 pin power supply. The 770 came with a 2 x 4 pin molex to 6 pin and a 2 x 6 pin to 8 pin converter. My PSU has two 6+2 pin PCI express cables. Should I use the converters or the PSU's cables.