Eggz :
AMD publicly (but quietly) announced that it completed a $33 Million upgrade to its FinFET process, which will result in a die shrink from 28nm to 20nm. The Titan X is at 28nm.
https://www.sec.gov/Archives/edgar/data/2488/000000248815000040/q215991.htm
[We made a] charge [in the second quarter of 2015] of approximately $33 million associated with a technology node transition from 20 nanometer (nm) to FinFET.
https://www.sec.gov/Archives/edgar/data/2488/000000248815000040/q215991.htm
I think that means products originally going to be on 20nm have been moved to 14nmff, ie stuff not out yet. 20nm never worked out for bigger chips.