I currently have a single monitor paired with a GTX 970 Strix. I am very interested in gaming across 3 screens at 60fps. Obviously the 970 is going to have a hard time rendering 3k. What I was wondering is; Would 2-way SLI with 970s run 60fps on ULTRA on triple A games, for instance, GTA V.
At 5760x1080, yeah, I'd say two 970s in SLI would perform more than adequately. Not sure how GTA V will run at those settings though.
I ran a 1080p 1 over 3 setup for awhile with 3 GTX 670's. I started with 2 then picked up a 3rd off eBay after the price dropped a little. From my experience, 2 cards should be enough for most games at that resolution. A 3rd doesn't scale as well as 2. Meaning 2 cards usually doubles the performance, but 3 cards doesn't give near as much of a performance boost. It's only worth it if you already have a power supply that can handle the load and you can pick up the 3rd on the cheap. This was in 2013. I upgraded to R9 290's when they were released since my 670's where struggling with BF4 and I wanted to give Mantle a try.
I quite honestly would sell your current 970 and buy a 980. instead of sli,
I used to have dual 760 in sli with 3 1080p monitors and it worked but had issues, i will not do sli again but my problems mostly were caused by me having to turn surround off and on and then with surround off it disabled sli so i had to disable my other two monitors to re enable sli for a more demanding game... your mileage may vary but my opinion is sell the current 970 and buy one 980.
that card is 340$ so you probably could resell it for 200$ and a 980 is $560 if you were buying another 970 that would be 340 so if you resell the old one you could pick up a 980 for about the same cost.