Why would Nvidia bring 980Ti up to Titan X performance? What the hell is wrong with you Nv? They must have been high as a kite when they made that decision.
They've got to sell the dies with the small manufacturing defects somehow, if they disabled too much and sold it too cheaply they'd be hurting GTX980 sales and making less money on the bigger GM200 cores. I guess they have already made most of their money on the Titan X, I always see the Titan as a card aimed at those who want cutting edge technology before the rest of us plebs.