Assuming you're playing with mainstream 1080p 60hz monitor resolution.
GTX680 (2GB), GTX770 (2GB), GTX1050Ti (based on benchmarks results online).
Ultra max settings (with full AA) @ 60fps is possible.
Personally tried and tested on my old GTX770 (2GB), can even run Battlefield Hardline maxxed out settings 60fps too.
Ok. So 1050ti is good enough to play BF4 at ultra? How about starcraft2?
If what's needed is a 1050ti, I suggest getting the 1070 so that the graphic card can last longer in between games you play unless you are okay with changing gpu often.