It's just 25% overclock over 14nm shrink, all it is. will be. 2018, 7nm is just another shrink. 15% GCN optimizations don't count on it. FuryX wasn't particularly efficient compared to 390X. add 25% to it and you get the picture., assuming memory will not overclock (memory bandwidth is the same) it could be as low as 15%. Here where 15% GCN+memory compression comes into play to pull it back to 25%.
20% higher clocks and 15% architectural improvement. That gives about 12TFLOP/s.... or 40% more than Fury X. This doesn't tell you everything you need to know about gaming performance, though.
Polaris is insanely bottlenecked by memory - I estimated that RX 480 should have nearly 320GB/s of bandwidth for peak performance... and it would be about 20% faster as a result. Vega 10 is 77% larger than Polaris 10, so needs that much extra bandwidth to see the GCN improvements... or about 566GB/s. With 512 GB/s, we should see about 15% better relative performance than we see with Polaris - partly eaten up by GCN scaling... but we're still looking at a card that is more than double the RX 480 with only 77% more resources... but double the bandwidth.
That means Vega 10 will range from ~40% to nearly 70% faster than the Fury X, depending on how much other hamstringing of performance AMD does (ROPs, mainly). The strongest probability cloud is nearer to 50% than to anything else.
Vega 20 and according to Videocardz it won't come until 2nd half of 2018 (about 2 years). Volta will have come out long long before that and I'm not sure exactly what to expect as far as an improvement over Pascal but I speculate for now that it will be a good bit faster than Vega 10.
Vega 20 is a mid-range 2018 card and a test chip for 7nm. Looks like AMD plans on some pretty impressive improvements with Navi (or will tighten the gap between mid-range and the top tier).
Seriously, you won't see that kind of adoption rate in 1 year.
The majority of the market can now run DX12. Game developers address as much of the market as they can - with most being able to now enjoy DX12 or Vulkan, all new game engines will make use. We are already seeing nearly every new AAA title have support for one or the other. In a year's time, many top CPU-bound DX11 games will have DX12 patches and nearly every new game will have support at or shortly after launch.
Microsoft's free upgrade offer pushed a lot of people onto Windows 10 (that and their underhanded upgrade tactics...). I didn't anticipate moving to Windows 10 at all, but my ability to make it like Windows 7 (stripping most of the new Windows 10 garbage) while still benefiting from the core updates made it a worthwhile endeavor.
