Despite advances, these figures show that FPS in 4K is still not ready for prime-time even on top-class cards.
When there are cards that can handle it, I'll think about upgrading my 1920x1200 monitor. Until then, I'll wait it out, and so can my aging graphics card.
Part of the problem is that at higher resolutions it becomes more important to use high graphics settings (high res textures, better lighting effects, further draw distance), not less. So if you're interested in 4K gaming, you'll want to do it with everything turned up to 11. The exception to this rule is anti-aliasing, which decreases in value the higher the resolution.
All 4k'rs I know use SLI. (They have have nvidia cards,980's). I wouldn't be surprised if some of them got the new card. Me, i'm cool with my 1080p and my 970.