Skyrim worked for me at 7680x1080 (3x 2560x1080) without doing anything to it, didnt try it for long and havent tried it at the 1080 21:9, but i cant think of a game which hasnt natively supported it.
Plenty support it badly, like the Ubisoft games, with their 16:9 screen layers where the excess screen doesnt have it. So FarCry 4, in the snowy mountains, instead of having a fully frosted up vision, you've got vertical bars in the 'excess' area which are clear, and then this stupid effect sticking in the middle of the screen
The Crew does exactly the same thing with a police lights effect.
I also noticed Star Citizen does something similar, theres a loading screen and just before you're in, you can see the hangar loading up and things popping up in the scene, but theres an 16:9 image still there in the middle trying to hide it all from you
Its equal parts annoying and amusing.
FarCry 4
Star Citizen
I had to fake this, i'd tried taking a screenshot when it looked like this, however by the time it was able to process it it was the loaded hangar, so as i had the loading screen with black bars, and the actual hangar, i just created the same effect you see for 0.5-1.5sec to hide the pop-up in the scene which used to be present.
