can be a bottleneck for 1080/30, almost certainly will be at 1080/60...
Is the Esram not also a potential bottle neck since its bandwidth is needed if used as a frame buffer? on top of the ROPs, especially if they plan to use 16mb of it for Tiled resources from their Tier 1 DX11.1
I think I read that you can get 1080p from the other 16mb without AA