Just so I understand correctly, your nMP 6 core with the D500 cards is performing about the same under Bootcamp as it is under Mac OS when running the Elemental Demo? If so, did was CrossfireX enabled under Window 8?
The reason I ask is that I’m also in the valley of decision with regards to a computer. I’d like to stay with Mac for the rest of my work and use Bootcamp for playback of the game. I’m not developing commercially. The project is for research using the Oculus Rift and highly detailed/realistic scenes like the Elemental and Blueprint demos. Fortunately, the OR only needs 1280x720 resolution. However, They recommend a frame rate of 85 fps.