I have 2 780 Ti Superclocked GPUs in SLI across 3 17" monitors (they were free
). Triple monitors cuts my FPS by about half on Arma 3 when playing King of The Hill.
I'm getting about 30 frames on KOTH. It's on the low end of frame rates, but very much playable and I still rape bodies like it's cool. I might turn off Suround when/if I get a 28" G-Sync monitor. Honestly, after playing Arma with 3 screens, playing with just 1 makes it feel like I'm running around looking through a scope
.
Some other game modes on Arma 3 I can get 75-80 frames with 3 monitors. Just pretty much depends on the server and game mode your playing, your CPU power, and GPU power.
On BF4, CS:GO, TF2, and GTA V, I can get about 180-230 frames, but my monitor can only keep up with about 75 fps fluidly.