The 5770 scales awesomely. 5770's are low powered too, so although your PSU is of dubious quality, you will probably be ok. I would upgrade if it were me though. If overclocking, test the 12V rail with a multimeter when under load to check the specs. This would be a better buy: http://www.newegg.com/Product/Product.aspx?Item=N82E16817139005