AMD already has HBM chips out (Fury X and Fury) and already has a shipping chip with 32 GB of memory (S9170). If you are willing to work with OpenCL the double precision rating of AMD chips is very compelling (look at the W9100 that has been out for a while now has a peak rating of 2.62 TFLOPS double precision!). I am looking forward to HBM equipped firepro cards where the double precision support isnt gimped.