I have the newest drivers (using driver sweeper of course for clean install) 313.95 Beta. When monitoring my GPU usage using EVGA precision, Only my primary card is used.

I have 3 way SLI for GTX 480's. They work fine in Far cry 3, Metro 2033, etc. They all are being used, and I am able to max those games out fully. Crysis 3 only is using a single GPU.

I have seen other AMD related crossfire posts. Please Crytek address this

I was having the same problem all you have to do is add the "Crysis 3 MP Open Beta.exe" to the crysis 3 profile using nvidia inspector and then sli will work