Asus matrix 7970 Platinum

what is your opinions on this asus 7970 im debating getting one as i cant decide on a gpu upgrade. what are the power requirements/ recomended power supply. im running a i5 3570k overclocked to 4.4 at the moment. what do you guys suggest. also i have a 650 atm so what performence boost will i see?

Get this one : http://www.newegg.com/Product/Product.aspx?Item=N82E16814161431

99% the same card as the 280x, but cheaper.

A good 500W PSU will be enough.