Yes Watttool is gold. And NEVER use afterburner with rx400 - it fucks up cards badly - DDU and afterburner uninstall may not even help to fix fan issues.

Not long ago on a mixed system with 470 and 370 I've used AB to control 370 fan, as it works there better. And the only way after that that I could manage rx400 cooling is when AB was loaded with the system and applied custom fan pattern, which was pain in the ass to do properly, as it required a single graph for 3 types of cards. Also the smoothest control of fans in the built-in one ... It took sometime to get rid of the necessity of the AB app on autostart.