It looks like AMD is going to confuse us once again by changing the naming of their new graphics cards. For the past two generations we had “R7” for entry-level through mainstream and “R9” for performance through enthusiast cards. The new naming seems to remove the number and replace it with a letter.
The photo you see above shows a picture from AMDs Macau Event. Here you can see that the card says “powered by Radeon RX 480“. So they could be going with “RX” instead of “R9” for the new series of Polaris graphics cards.
The “RX 480” was able to run “Doom” (2016) at 2560×1440 @ 144 Hz, with the OpenGL API.