Haven't had chance to read all of the replies but if your getting really low FPS with SLI, turn off DETAILED GRASS. Its been broken for about 6 months now and kills FPS. With it enabled on my GTX 980 SLI I get 40fps, with it disabled, I get 100fps! Not sure if its a similar story for AMD and crossfire.
5/7/15 at 1:29pm