Not sure what may have caused this, but figured I would report it here to be safe. Could have just been an extremely rare fluke.
I was doing some things at my desktop and using Chrome browsing the web when suddenly my reference model RX 480 just started ROARING out of nowhere at about 100% fan speed.
Here is what WattMan shows while it's running at the full speed:
I cannot find any reason or setting that made it happen, but it did. First time this has occurred for me
Not sure if this means anything or if it's just a fluke, but wanted to point this out and be safe. It really scared me when the silence was broken by this beast