Korean tech site HardwareBattle has leaked an image of what is reputedly an AMD presentation slide. It refers to Polaris as the fourth generation of GCN and thus is it expected to be the microarchitecture present in the Radeon 400 Series including the 'Greenland' GPUs.
A VideoCardz report takes the claims further. Rather than being a new generation of Graphics Core Next, a GPU microarchitecture series kicked off by AMD in 2011, it believes that Polaris is a replacement for GCN. The above slide reads "Introducing the Polaris Architecture. Our guiding lights is to power every pixel on every device efficiently. Stars are the most efficient photon generators of our universe. Their efficiency is the inspiration for every pixel we generate."
Reading further between the lines both VideoCardz and WCCF Tech think that an astronomy Tweet by head of AMD Radeon Technology Group, Raja Koduri, provides a hint about the upcoming Polaris-based GPU performance. The Twitter exchange between AMD marketing director Chris Hook and Koduri is read as code speak for the new microarchitecture...
As you can see above, Koduri makes reference to Polaris being "2.5 times brighter" than back in the heyday of the ancient Greeks. To VideoCardz and WCCF Tech writers this is apparently code for the performance/efficiency hike on offer from the Polaris microarchitecture GPUs like 'Greenland', produced on the new 14nm FinFET LPP process. Whatever the case I hope AMD's future is at least 2.5 times brighter in 2016 and it brings some highly competitive, if not market leading, products to consumers.
File this one under 'industry rumour/astronomy'.