Looks like guys from 3DNews forgot to adjust their clocks..

Peak frequency – 2126 MHz.

Machine translation of the conclusion:

Thus, a small compromise in specifications GeForce GTX 1080 Ti looks rather an attempt to reduce the cost of video card than to differentiate it from the TITAN X. More addition, NVIDIA has improved “physical” parameters of the board – the efficiency of the cooling system efficiency and power, eventually depriving TITAN X residues practical values. The latter, at a price of $ 500 above, the buyer can give only moral satisfaction from owning a bit more powerful GPU. At TITAN X share also remain specific scenario calculation problems, which are absolutely necessary to have 12 GB of RAM.