Yep +1 for Radeon Pro.
FC3 just has problems. I get stuttering (without RP) even with CF disabled. 3 cards is better than two but honestly, it's just bad regardless. Considering it's a Gaming Evolved title, it's a bit embarrasing IMHO for AMD to be this bad in it.
FYI... I've been running RP for a long time, and I've found (for me anyway) that it's most effective if you set the dynamic fps control to roughly 10FPS less than what you'd normally see in FRAPS. That usually gives you enough room to account for any low FPS points you might encounter and keeps things nice and smooth. Even though I'm frame capped, I still get to enjoy all the eye-candy just at less than max FPS.
I'm really hoping the frame pacing driver is as good as it appears to be... If it is I'll be set for another year+ with my current build.
W8.1 Pro: Corsair Air 540, AX1200
ASrock Extreme 4, i7 3770k @ 4.8Ghz
32GB RipJaws @ 1600
2x EVGA 780Ti's
Crucial 512GB + 2x 3TB
Creative X-Fi Titanium
Dell U3011 + WFP2407