According to AnarchX on the Beyond3D forums, a senior engineer at AMD has posted about a project he's working on - which just so happens to be the Polaris GPU from AMD.
The engineer notes that the die size of Polaris will be 232mm² which is just one tier of the Polaris pie. Now remember, Polaris is being made on the 14nm process - so if we compare it to a 28nm part, it would be a 464mm² die - at the same TDP levels.
We know that AMD wants to increase performance but keep the power numbers low, so we should be expecting some huge improvements in performance, without much more pressure being applied to power numbers.
But then we have to remember the tweets from RTG boss Raja Koduri, who said before the Polaris unveiling in Sonoma that "Polaris is 2.5 times brighter today than when Ptolemy observed it in 169 A.D". If Koduri was talking about 2.5x performance, then we're looking at the 232mm² GPU being compared against a 28nm 580mm² - with the same power levels - which would be insane.
Of course, we could be looking at just a rumor on a LinkedIn profile and completely off the mark - but if we aren't, we should be getting even more excited about AMD's next-gen Polaris GPUs.