Is anybody else here having fan problems with their RX480 after updating to 10.12.6? Mine are stuck at full speed. Usually you just run the old OpenGL extension viewer trick and things calm down but that's not working anymore. smcFanControl also does nothing. I'd have said that there was some sort of errant process sucking down GPU cycles but the card is physically running cool. UPDATE: Ok, so I've reset the PRAM, the SMC, tried the card with a completely fresh install of 10.12.6 and the system is locking up along with the fan noise issue persisting. None of these issues happen with my old 4870. At this stage I have to conclude that there is a non zero probability that the latest macOS update is breaking compatibility with the RX 480. Final Update: I actually solved this but I'm posting the reason here for anybody who's made the same mistake that I did. So, what I failed to realise is that 10.12.6 actually added native support for the RX 480, so when I did the usual driver hacking, I was inadvertently causing a conflict. Deleted the offending PCI IDs and everything is working normally again. Thanks to everyone that offered help!