I just recently built a pc with an AMD A8-3850, still at 2.9ghz, with 8gigs of ram. I've been playing the battlefield 3 beta, and using the gpu on the APU, I've been getting 30-37 fps outdoors, and indoors, such as the metro map, I get 40-50. This is on auto settings, which is about the equivalent of medium settings, at what I believe is about a 720p resolution (can't remember exact resolution right now). I have played on Caspian Border, with 64 players, and it still handled it fine. I wouldn't be worried at all about running it with a 6670 xfire.

I just recently built a pc with an AMD A8-3850, still at 2.9ghz, with 8gigs of ram. I've been playing the battlefield 3 beta, and using the gpu on the APU, I've been getting 30-37 fps outdoors, and indoors, such as the metro map, I get 40-50. This is on auto settings, which is about the equivalent of medium settings, at what I believe is about a 720p resolution (can't remember exact resolution right now). I have played on Caspian Border, with 64 players, and it still handled it fine. I wouldn't be worried at all about running it with a 6670 xfire.