I have an HP Pavilion p6608f and according to the command prompt the motherboard is an MSI 2A9C. My PSU, the Antec VP450F (450W) doesn't have an 8pin PCIE to plug into the GeForce GTX 960 I'm trying to install (recommended 400W PSU), it only has a 6pin PCIE available. Would a 6 to 8 pin PCIE adapter be acceptable in this case because I have wattage to spare?