I updated driver to 26.20.11015.5009 22/05/2019 & found the cooling fan was jumping from 25% to 100% for a 1°C temp rise. Rolled back driver to 26.20.11015.1003 but this didn't solve the problem.
This is a very recent issue that has developed
Windows 7 Pro x64
AMD FX 8350
24GB DDR3 RAM