I think people here might be interested in this thread over at OCUK.
(Many posts later with others confirming the issue.)
haaammit on OCUK said:Hi - quick question regarding my RX480 4Gb card. For some reason, the load always seems to be at 100%, even with no games or windows open. I have used both GPU Temp and GPU-Z and they both report 100% load and a temperature of ~80 degrees. Using driver 16.7.3 (there is a newer driver, but it's beta)
(Many posts later with others confirming the issue.)
AMDMatt on OCUK said:We're investigating this one internally folks.