Some interesting info surfaced on the web the past day or so. As you guys know, AMD is to release GPUs based on Polaris, however a recent AMD roadmap shows Vega and Navi Architectures. Vega is the successor to Polaris with HBM2 memory to be launched in the 2017 time-frame. An employee on their linked-in page noted Vega to have 4096 shader processors.

It seems that after Polaris in 2017 VEGA will make an appearance, the name is tagged with HBM2 meaning that HBM2 likely will not make it onto Polaris. Vega is the brightest star in the constellation Lyra, the fifth brightest star in the night sky and the second brightest star in the northern celestial hemisphere, after Arcturus. Next in line in the 2018 timeframe we see Navi with the two keywords being scalability and Nextgen memory.
  

 
Now the juicy part, The LinkedIn profile of Yu Zheng (who is an R&D manager at AMD) (info was removed btw) shows "shader processor" (stream processor) count of Vega10 to be 4,096, have a peek:
  

Interestingly enough, that's the same shader processor number as Fiji (Radeon R9 Fury X). Since the info does not state what model GPU (mid-range/high-end/enthusiast) it'll be used for it all remains guess work in terms of performance. We do know that perf per watt will increase significantly over Polaris and that these GPUs will be fitted with HMB2 graphics memory.

Since we are on the topic, "Polaris" architecture based names are oozing out. A high-end chip will be called "Ellesmere" or Polaris10. There will be a mid-range GPU called "Baffin" or Polaris11. And then "Ellesmere" is rumored to get 36 GCN 4.0 compute units, which works out to 2,304 stream processors; and a 256-bit wide bus, indicative for GDDR5/GDDR5X with 8 GB memory amount. 

It's going to be an interesting year.

AMD Greenland Vega10 Silicon To Have 4096 Stream Processors?