GP100 is what lot of us wait.
TITAN X successor. It would be stupid if someone didn't bought
GTX980Ti or TITAN X before one year and now chase 10% stronger card. Only 10-20% after whole year of waiting.
AMD could launch slower card similar as Fury X and premium with HBM2.
In that case they will be in advantage compare to GDDR5X.
But many people want premium card, first chip after GK110 build and for professional purpose.
Probably GeForce with 16GB and other with 32GB but not as GeForce.