Nvidia GTX980Ti Review
The important questions, away from the pure "how fast is it" ones, are how does it compare to the GTX980, and is it good enough that 4K is a realistic proposition, or is that resolution one that's still a tomorrow away?
How does it compare to the GTX980, very well. Consistently better as would be expected from something that beats a Titan X. Is it enough for 4K? Probably not quite yet. We're getting closer though.