I got a neighbor running none other than a K7S5A on 250w PSU (he didn't buy a new one for it, but runs fine). However, it is an Enlight, and the thing runs any low-end system fine (the same model PSU in my machine wouldn'tlet meplay serious sam, but I could doPSX emulation no problem), but if you're not sure about it being a good PSU, then get a good 300w or better.