Depends on which settings you will run the games. If you would put the settings on ultra, to run it "smoothly" it will probably have to be at 720p, which is not advisable as it won't really look good. On 1080p, you'll probably have to turn it down to medium settings, but that will still look a lot better than ultra on 720p.
If you wanna enjoy the upcoming, demanding titles on ultra in 1080p, I'd expect only a GTX 770 (or 680, which it's based on) and better will do a really good job in terms of fps (as far as Nvidia cards go).