I was able to reduce my temps by 10-14C with same performance (FPS) in WoW and Fallout 4 by using Global WattMan in Radeon Settings.
I selected to "Auto undervolt GPU" and then started a game. Played for 45 minutes and peak temp was 76C with average around 74C.
This morning in the same game/environment my temps hit 86C on average and higher depending on the game.
I will continue to cautiously tweak the settings but depending on your card, your mileage may vary.
This is my first AMD card in 7 years, I want to make it work but I am very new to the Radeon software.
If you have advice please share.