The site claims the GeForce GTX 980 Ti will not be a cut-down version of the GeForce GTX Titan X's GM200 GPU and that it will feature the same amount of CUDA cores as the Titan X. The rumor suggests the GeForce GTX 980 Ti may be a higher-clocked GM200 chip with half the memory of the Titan X.
If there's any truth to this, you can expect the GeForce GTX 980 Ti have 3072 CUDA cores, a core frequency of over 1100MHz, a boost frequency of more than 1200MHz and 6GB GDDR5 memory clocked at around 7GHz.