well some micro atx cases can't take a regular atx power supply (a micro atx supply is a lot shorter). The invin v500 does, so i put an antec 300watt in it. I stuck the 145 watt in another system, and its voltages weren't all that great. AMD's list says that the durons can run on 145 watts , but i wouldn't personally do that, especially with a voodoo5 or something