Pictures of an upcoming AMD Radeon "Navi" graphics card bare PCB made it to the web over the weekend. The picture reveals a fairly long (over 25 cm) board with AMD markings, and a layout that doesn't match with any reference-design PCB AMD launched so far. At the heart of the PCB is a large ASIC pad that appears to be within 5 percent of the size of a "Polaris10" chip. The ASIC is surrounded by eight GDDR6 memory pads. We could guess they're GDDR6 looking at the rectangularity of their pin-layout compared to GDDR5.
Source:
https://www.techpowerup.com/254992/amd-navi-graphics-card-pcb-pictured-uses-gddr6