For those who are late to the party:
Though I think they might have jumped to the conclusion that this is OGSSAA: there's no AA filter being applied when the image is rendered at the larger resolution, is there? I use a 1080p monitor and I made two custom resolutions: 2048 x 1152 and 2560 x 1440. Anything larger is... too much for nearly every game since I only have a single GTX 680.
So I don't think this is OGSSAA, since it doesn't give me amazing AA. It is however, essentially the same thing as the 3D resolution setting in ArmA 2. Oddly enough it doesn't work in every game, but most. When running 2560 x 1440 there is a noticeable increase in picture quality/clarity in most games, and when used in tandem with AA (especially forced external AA via NVIDIA Inspector, and especially forced supersampling), AA seems to be improved. I also noticed that gamma/contrast/brightness settings must be adjusted.