You can run it. The 450 GTS only requires a 450 W PSU. The minimum required PSU is of a 450 W. The MINIMUM though. Not sure about the maximum part. But I am pretty sure it can run the 450 GTS. You can go to coolermaster .com for a type of calculator that lets you know the total power consumption of your rig. It may not display it accurately but you can give it a try.