Based on the AMD Linux driver source code information and some other leaks, VideoCardz offers a bit of educated speculation about the specifications of AMD's Polaris GPU lineup.
Details popped up on the SiSoft Ranker of a Polaris 10 card with Device ID 67DF. It seems this model has 36 compute unit, 2304 stream processors, a 800MHz core clockspeed, a 256-bit memory bus and 8GB of GDDR5 memory clocked at 6000MHz. It's believed these Polaris cards will be replacements for the Radeon Rx 3xx series, the real high-end refresh is speculated to be Vega and may not arrive until sometime in 2017.
The specifications are definitely not high-end, but let’s not forget this just one of the Polaris 10 SKUs, so we don’t know if specs are modified for lower model.
I find it hard to believe that AMD would achieve two times more efficient Stream Processor going from GCN 3.0 (Fiji) to GCN 4.0 (Polaris 10), so I doubt this card could beat Fury X. Judging from memory capacity, we might be looking at Hawaii replacement with new 8GB solution. Whether this is the Radeon R9 490X or R9 480X is something we can’t be sure just yet.