The 6990 has 2gb of Vram while the 590 has 1.5gb. In larger resolutions, especially 3 30", this could be important. AMD also has better scaling, and can allow for more monitors and orientations.
Personally I wouldn't bother with 3 monitors unless in portrait. Many games do not support it landscape well. Everything on the side monitors are stretched like hell and you have to turn your head to see the hud. When a notification occurs you may not notice it. It is pretty immersive, but not much games support it well enough.
Personally I wouldn't bother with 3 monitors unless in portrait. Many games do not support it landscape well. Everything on the side monitors are stretched like hell and you have to turn your head to see the hud. When a notification occurs you may not notice it. It is pretty immersive, but not much games support it well enough.