AMD has released a new set of Crimson drivers, 16.8.1, adding official support for their new 470 and 460 GPUs and fixing a few lingering problems. The last set of AMD drivers (16.7.3) were apparently a little iffy for 480 cards, and introduced problems with Wattman under-reporting memory limits. 16.8.1 claims to address all of those things.
As the patch notes have it, “Max memory overclock available on Radeon RX 480 being too low in Radeon WattMan has been resolved“. There’s also a specific fix for Firefox crashing when hardware acceleration is enabled (a persistent problem I believe, so nice to see that one gone), and a fix for AMD’s Radeon Settings reporting an error when updating drivers through that application.
Here’s the change-log, and list of known, remaining issues.