Inside sources claim that AMD's Navi GPUs are performing better than expected and could be launched in the first half of 2019 rather than the second. Previously rumored to be slower than the GTX 1080 from Nvidia, it looks like the red team managed to tune a few things and boost the overall performance. MSRPs are rumored to be in the US$250 zone.
https://www.notebookcheck.net/The-next-gen-7-nm-Navi-gaming-GPUs-currently-tested-in-AMD-s-labs.345301.0.html