As expected, AMD's Vega slideware has arrived. The company shared information about the architectural improvements it made but the juicy details like card details, performance, power consumption and pricing were not revealed. The company is also still clinging to a "first half of 2017" launch date so I think it's safe to assume we won't see any cards in decent volume until April at the earliest, and possibly even later than that.
For an in-depth look at the new architecture I suggest this article from The Tech Report. Among other things, it describes the new memory architecture, the new geometry pipeline with higher throughput per clock and improved load balancing, the new compute unit design, and the redesigned pixel engine. Another interesting new feature of Vega is the implementation of Primitive Shader, this is run on a more programmable geometry pipeline stage and has the goal to handle geometry data more effectively.
The site's reporter was also able to hold a Vega chip in his hands and took a picture of the package, which shows off the Vega GPU and two HBM2 stacks. VideoCardz took out the digital ruler and estimates the Vega chip has a die size of 520-540mm².
Additionally, there are a bunch of new Vega videos on YouTube. Here's a brief clip of Vega running Doom on Ultra settings at 4K: