I mean why is it so expensive? Is it better than GTX 1080Ti? What does it mean by 'Pascal Architecture' also what would be the general use of this expensive GPU?
The way GPU's work and sold is they have a core. In this case the GP102 core. Said core will have a limit of the amount of Cuda cores, VRAM, Shaders or whatever. In this case, the Titan Xp and 1080Ti (and inital Titan XP and even Quadro cards) share the same core. However the 1080Ti is slightly cut down with some of those core's disabled a GB less of Vram and so on.
Now to go against what was said, the Titan Xp is not really any more specialised (at least significantly) then the 1080Ti. Unlike the very first Titan card's and new Titan V, starting with the Titan X (Maxwell) Nvidia removed most of the elements such as double precision performance that made the card standout. Now the extra 1GB may help in very specific workloads and Nvidia did release driver updates only after Vega launched to the Titan Xp to help in some workloads.
So long story short, the current Titan Xp is really mostly a gaming card and it has a slightly fuller core then the 1080Ti. This does mean the Titan Xp does outperform the 1080Ti for gaming. But the issue is price to performance, it does not outperform the 1080Ti by much, yet costs much more. The other side is, Pascal work's based on temperature's with lower temperature's = better performance. As a result aftermarket 1080Ti's with better cooler's will be able to boost higher and close the real world performance gap to the Titan Xp on its blower design (unless you ramp said cooler up) Right now the price premium is in part thanks to the name it carries, and simply put before the Titan V, is the best performing gaming card you can buy once you get it under water / happy to sit with the fan turned up which some folk are happy to pay for. Most people are happy to take the smaller performance hit (or non existent if comparing good 1080Ti cooler vs Blower Titan Xp) and save the cash.
so GTX 1080Ti is best gaming gpu right? What is best overall 10xxTi GPU? I Currently have EVGA 1060 FTW+ 6GB ACX 3.0