http://www.evga.com/products/moreInfo.asp?pn=01G-P3-1526-KR&family=GeForce%20500%20Series%20Family&sw= according to this they require 300w minimum, Although the one I have said a minimum of 400 watt my power monitor rarely goes above 200w while gaming, although I do not have any other extra peripherals that weren't standard. PSUs are not that expensive though you can pick up a 600w for less than $50