I would take the 7950 because of more memory e.g. Also bf4 should not be much different to bf3 and there I suspect 50-70 frames at 1080p.
I agree. The 3GB of VRAM with the 7950 will take you further down the road, and BF4 actually recommends 4GB of VRAM. When Mantle is implemented into BF4, there could be some nice performance boosts. I really think Mantle has the potential to make a huge difference.