I was checking something out at the NVIDIA web-site FAQ's for my older graphics card. I found this by accident and with quite a lot of joy. Take it for wat you will. Anyways....Here's the link to ASUSTek's site where you can get a rough(?) estimate for the power supply you may need: http://support.asus.com/PowerSupplyCalculator/PSCalculator.aspx?SLanguage=en-us If anyone else has another site, or has anything to add, please do so.