2 HD 6950s in CF will perform close or maybe a little bit lower than HD 6990. HD 6970s in CF will perform better than a single HD 6990. and as long as you're going Eyefinity, i would suggest you to stick with the HD 6970s in CF, just make sure your PSU is capable of handling it.
I can assume this mb will work for crossfire of the 6970's? GIGABYTE GA-Z68XP-UD3 LGA 1155 Intel Z68 HDMI SATA 6Gb/s USB 3.0 ATX Intel Motherboard
I keep reading that not all games benefit from crossfire. That would suck if Im building this specifically for bf3 and it wont?
well, all the modern games benefit from CF and SLI, most of CF / SLI issues are related to drivers and hardware configurations.
You said you're going to Eyefinity, and no way... you need a CF setup in order not to experience a lag of FPS when running such games in a such higher resolution 5760x
if you don't wanna feel the hassle from CF / SLI issues so a Dual GPU is your best option.
I appreciate your input.. I will go with the 6970's. Now Im looking at motherboards.. Another thing to figure out.. trying to figure out whats best for ssd and the i7-2600k, with crossfire hd 6970.s... ugh..
Toms recently reviewed a round-up for some LGA 1155 MOBOs, you can check them and pick up the recommended one.
For SSDs i don't have much experience with it, as also i'm trying to pick up one for me, but the most i have been searching recently is Corsair Force GT and OCZ Vertex 3, they both have the same outputs and got great reviews