as an example, I run 3 monitors which amounts to 6MP. BF4 uses 2.6GB on max settings. You'll be running 3.6MP so no problem. 2 monitors are worth it as you have the split down the middle, making many games unplayable. 3 monitors at your resolution might be pushing it for both Vram and GPU power. But it's the old case of (up to a point) the more Vram you have the more it'll use. So you might get away with 3GB. If running 3x high res monitors, R9 might be best to be safe.