JackNaylorPE :
VRAM is going to be very very important at 7680 x 1440....
4 GB seems to work well enough at 5760 x 1080 .... but you're now talking 78 % more real estate.....scaling would put ya at 7GB so the ^GB models might suffice.... but I have not seen this resolution addressed in the trade press
Nah, vram usage does not scale like that. Your frame buffers are very small to begin with. Like 20-30 mb's at 5760x1080, so you are only talking about a little more VRAM usage for frame buffers. Most the vram usage go into textures, which does not change from increased resolutions. AA has a tendency to also kill vram, but at that resolution, you probably won't be using it much, not just due to the extra PPI, but also the horsepower needed to get good results.
2GB tend to work just great at 5760x1080, I doubt 3GB would give you an issue at 1440p x3, unless you try to use a lot of AA or mod the heck out of Skyrim.
And when people show their vram usage from their Titan's, realize that just because XXX amount of vram is used, does not mean that that is required. You see a lot of 3GB cards showing 2.5gb usage, but 2GB cards have no slow downs at all with the same settings. If a card has extra Vram, the program just doesn't have to swap out textures as often, allowing more vram usage to pile up.