So I also have this issue and have found that as standard my setup was changing the fan speed massively at 60 degrees. For my set up it had a few break points for fan speed. they were at 40, 60, 70 and 90 degrees. The problem was my CPU temp was always sat around the 60 degree mark with normal usage (light browsing on chrome and some background processes). It would go from 55 to 62 degrees or there abouts. The issue for me was as soon as it went over 60 degrees the new fan speed would kick in and try and drop the CPU temp.
The fix for me was to manually change these break points in the BIOS. instead of 40 degrees with 25% fan speed and 60 degrees with 65% fan speed (the standard figures that were set in the BIOS) I changed it to be faster at lower temps and then changed the 60 degree break point to 65 degrees. This stopped the issue of it bouncing up and down all time.
Not ideal to have to change these manually I admit, but I tried lots of WIN10 changes, BIOS updates, AMD4 driver updates and reseating the CPU with new thermal paste all to no avail. Hope this helps others, personally I will wait for more updates and see if these change things and if not will probably either see how this temporary fix goes, or try an alternative fan.
