All the imacs i've seen have intel cpu and a dedicated amd gpu. i've seen a 21" with a 6750m and a 24" with a 6970m so how is going to amd cpus going to be anything but a massie downgrade to cpu power if they still use the same gpus! it doesn't make any sense. unless they do it on the mac book pros which all have integrated gfx by the look of it (except the retina ones) then way you say is probably true!
I'd imagine that's the idea, perfromance per watt on typical usage scenario's look to be better, so for the macbook means longer battery life *cough* smaller batteries *cough cough*. Alternativly smaller, sleeker, neater package without needing to design discrete gpu's in for the imacs without too much compromise on gpu power.
Realistically how much of their consumer base is going to miss the cpu power? Most people using a macbook are busy looking and feeling cool while doing the exact same mundane stuff nearly everyone else does on a laptop. GPU accelleration should help out for the pro users, who do the exact same stuff as their pc equivalents but would rather look and feel cool while doing it.
And for the near future AMD is going to have the edge on Intel for gpu quality/capability.



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