REVIEW:
Triple Monitor Gaming: GeForce GTX 590 vs. Radeon HD 6990 - TechSpot Reviews
Go through the graphs. You will notice one thing though. GTX590 decisively beats HD6990 in only 2 games(both are nVidia TWIMTPB titles, Crysis 2 and Mafia II). Yeah you are wondering Far Cry 2, but AMD pulled it off(11.4 makes huge gains on Far Cry 2 check here: AMD Catalyst 11.4 Windows 7 Driver Analysis :: TweakTown USA Edition)
Triple Monitor Gaming: GeForce GTX 590 vs. Radeon HD 6990 - TechSpot Reviews
Go through the graphs. You will notice one thing though. GTX590 decisively beats HD6990 in only 2 games(both are nVidia TWIMTPB titles, Crysis 2 and Mafia II). Yeah you are wondering Far Cry 2, but AMD pulled it off(11.4 makes huge gains on Far Cry 2 check here: AMD Catalyst 11.4 Windows 7 Driver Analysis :: TweakTown USA Edition)
Maybe we already knew this but HD6990 is indeed the better card when it comes to what it was built for, extreme gaming at extreme resolutions. By no means if 1920x1080 a place for such cards mind you.