IGN is reporting the GPU will be roughly 6x more powerful than current hardware. And based on the 6670.
http://www.ign.com/articles/2012/01/24/xbox-720-will-be-six-times-as-powerful-as-current-gen
They also are calling for a 2013 release. If true I'm going to guess they're going roughly the route of the Wii with less than top of the line hardware. A 6670 can't even run current games at max settings on 1080p. Granted a lot of stuff can be optimized with a dedicated gaming unit but I'm still a little disappointed that we could be getting a roughly 3 year old architecture next year and not even a top of the line chip at that.
http://www.ign.com/articles/2012/01/24/xbox-720-will-be-six-times-as-powerful-as-current-gen
They also are calling for a 2013 release. If true I'm going to guess they're going roughly the route of the Wii with less than top of the line hardware. A 6670 can't even run current games at max settings on 1080p. Granted a lot of stuff can be optimized with a dedicated gaming unit but I'm still a little disappointed that we could be getting a roughly 3 year old architecture next year and not even a top of the line chip at that.