I'm currenlty running a pentiumD 820 (on a 24 pin, 775 lga motherboard) with a 600 watt 20 pin Ultra brand power supply, and it runs without a problem. From my understanding 20 pin power supplies are fine on 24 pin motherboards, the only concern is y how much wattage your psu has. Just make sure you have a little bit of power to spare on top of all the parts in your system, and you should be just fine.