The GeForce GTX 1070 Ti has 2432 CUDA cores, which puts it within striking distance of the 2560 CUDA cores of the GeForce GTX 1080. The main differences are the clockspeeds and the memory. While the GTX 1080 has 8GB GDDR5X memory clocked at 11GHz, the GTX 1070 Ti's 8GB memory is of the GDDR5 variety and is clocked at just 8GHz.
Both models have a base clockspeed of 1607MHz but the GTX 1070 Ti has a Boost of just 1683MHz, whereas the GTX 1080 clocks up to 1733MHz. There's no lock on overclocking but most of NVIDIA's partners did not get permission to launch factory overclocked cards.
You can expect the GeForce GTX 1070 Ti for $449 on November 2. Reviews will follow on that date.