Word is going around that AMD's future EPYC "Rome" generation will up the core count to a massive 64 cores per package, resulting in a total of 128 threads. These processors will be build on a future 7nm node, thus they aren't likely
to hit the market until 2019 at the earliest.
One design will have 12 cores per die (x4 for 48 cores per package) and the other will have 16 cores per die (x4 for 64 cores per package). The reason why this is interesting is because AMD is, apparently, expecting to sell enough volume to warrant multiple chip designs, rather than just making a flagship and filling in SKUs with bin sorting and cutting off the cores that require abnormally high voltage for a given clock rate as parts with lesser core count. (That will happen too, as usual, but from two different intended designs instead of just the flagship.)