Sorry, but a GPU released 2 years later with roughly the same performance as R9 Fury X just makes absolutely no sense at all. Maybe AMD isn't the top dog when it comes to engineering (or marketing) at the moment, but they still aren't that stupid. They had a projection prototype for sure and if that showed essentially the same performance as R9 Fury X they'd scrap the whole thing back then already. And if they for some reason are just going with it despite those findings, then AMD has some serious issues. And I don't think they do.
I mean, lets be realistic, when you change so many things in the rendering pipeline of the graphic card and still somehow yield same performance as R9 Fury X, things just don't add up for the leaks.
Not to mention, if they wanted to keep 3DMark scores 100% private, they could run the thing offline and still get the numbers. So, this must be some sort of baiting or something...