It depends on the card and the game, Example, I've just had delivered yesterday a 1440 res monitor, BenQ BL2710PT in fact, and I'm using a Galax GTX 970 exoc with it. Now, I don't have any new games, but I've currently been spending the day trying out various older games, Crysis, crysis2 and crysis 3 and COH tales of valor. Also gave heaven and valley benchies a go. Now, all I've had to do in Crysis 3 to get average 55-60fps in game is turn down shaders to high from very high, thats one setting. This is obviously dependant on the game level being played and whats on the screen at the time. It can drop to around the low 40s, but only once have I seen below that figure. I can't see any visual difference, but the fps increases sufficiently to give a lot smoother gameplay which also negates the input lag of the screen which is noticeable but not obtrusive.
My point being that I think a lot of people here are assuming that having to turn down a setting or two is the end of the world, it isn't. If you're a hard core gamer then this would probably be an issue, but for a lot of people, like me, its not. If I buy a few games in the future and encounter Vram issues that cannot be remedied by reducing one or two settings, then I will replace the 970 and get an AMD replacement, I certainly will not be giving Nvidia any more of my hard earned dosh (the issue I have with them is misrepresentation of a product that "THEY" supplied and giving absolutely NO explanation, apology, or anything related to this debacle, thats what I'm a bit peeved with.
And good on Ocuk and Gibbo, et al wrt their customers, absolutely top notch.