I have a 700 watt psu and want to replace my 5770 gpu with a 7950. I only see a 6+2 cord labeled pci (6 plugged into 5770) and a p4 connector that has the exact same configuration as the 6+2 minus the 2. I know the p4 is for older motherboards. Was wondering if its the same wattage as the pci plug? If not I guess I'm screwed getting a 7950.