For Future 1080 TI Owners- Don't worry that much about clocks pass 2000mhz.Unless you are benching and aim for highest bench scores you should NOT be concerned about Max OC on core pass 2000 Mhz.
We are talkig here about 3,5- 3,8% difference on Core Clock speed 2000Mhz vs 2050-2078 speeds.
That said it gains you absolutely nothing in games.
I have run some tests in Witcher 3 today and I have been testing in same area 3 different clocks:
2038 core, 2050 core and 2063 core.
The total difference between 2038 and 2063 core was- 1 fps in 1440p. We are talking here about scenario where I have anything from 88 fps to 105 fps in game. 1 fps is nothing.
Between 2038 and 2050 there was no difference at all in performance.
That being said- you could see 2 fps difference in games between 2000mhz and 2075mhz . And that not being guarantee as you can have better performance on lower clocks, depending on how good chip you got.
So if your card is 2000 mhz then you are winner.