Eximo :
The 1080Ti might be the "Black edition" fully enabled GP102, in which case it would have the same memory as the Titan XP. That used to make the Titan worthwhile to some people. I've always been of the opinion that is what they would do. Just not enough room between the 1080 and Titan XP for another grade. If they do release it as a cut down version, the price had better be amazing to compete with Vega.
GTX780 3GB, Titan 12GB, GTX780Ti 6GB, Titan Black 12GB
GTX780 3GB, Titan 12GB, GTX780Ti 6GB, Titan Black 12GB
Original Titan and Titan Black were 6GB cards. 780 Ti was 3GB.
https://en.wikipedia.org/wiki/GeForce_700_series
I was thinking a generation ahead I think. Just remembered the 780Ti was a big deal because it was fully enabled and was so much cheaper than the the Titan.