GP100 and GP102 are same chip
The site claims the GP100 and GP102 are essentially the same chips, the main difference is the first uses the NVLink interface while the latter is PCI Express, but the feature set of both chips is the same.
The new Titan card reportedly has the same display outputs as the GeForce GTX 1080/1070, minus the DVI connector, and has a 300mm long PCB. Some engineering samples have 8+8-pin power while others use 8+6-pin configuration.
Performance 50 percent greater than GeForce GTX 1080
NVIDIA is still finalizing the clockspeeds of the consumer version and there should be two versions of the Titan boards; one with 12GB HBM2 and another one with 16GB HBM2. I'm not sure if the HBM2 part is accurate as other rumors indicate this memory isn't widely available yet. Performance-wise, NVIDIA is shooting for 50 percent higher performance than the GeForce GTX 1080 Founders Edition and VR World claims performance will be bound by the CPU:
Even Core i7-6950X isn’t enough to feed all the cards and in a lot of scenarios you could see an Intel Core i7-6700K, with its supreme clock (4.0 vs. 3.0 GHz) easily feed the GP100 more efficiently than Broadwell-E based Core i7 Extreme Edition. The running joke inside Nvidia is “don’t buy the 6950X – buy 6700K and a Titan” but we’re not sure that Nvidia will use this for an official tagline.