I have the ATI 4650 1gb.
Get the 4670 and you are good to go!
It's actually 55watts vs 70watts, but there is nice boost in performace for almost the same price:
http://www.hwcompare.com/3090/radeon-hd-4650-1gb-vs-radeon-hd-4670-1gb/
I actually want to upgrade to it since Im a cheap bastard xD