Ok, for newer processors, it is 24 pin, but if you have a 20pin, it will plug into certain MOBOs just fine. Just take a look at the MOBO, certain MOBOs are different, but assume 24pin for PCIe MOBOs. As long as pin 1 on the 20 pin power connector align up with the pin 1 on motherboard 24 pin power connector. Same apply to the ATX12V AUX connector, as long as its pin 1 on the four pin connector align with the pin 1 on the six pin connector on the motherboard, they should work.