I have been having the same problem for quite some time, and have also yet to figure out a solution.
The computer can be sitting idle for some time, yet the GPU temperature hovers around 72C with the fan only at 282RPM. Once opening any small graphics file, or doing something more than simple word processing, causes the temp to rise rapidly to roughly 89C before the fan kicks in at full speed, and very loud. The temp gets to about 94C before it starts to cool down to roughly 85C, the fan stops, then as the temp rises again to 89C, the fan kicks in again at full speed. This is very frustrating and annoying. I have tried uninstalling and reinstalling the software, without success.
Have you solved the problem yet?
I have this exact same problem. I've had my computer for a couple of years and about a year ago I noticed that the fan would periodically come on quite loudly. I know the fan has more than 2 speed settings, because sometimes the sound drops off a bit for a few more seconds before going quiet. I thought it was my CPU fan, but my son just installed monitoring software and we can clearly see its the GPU fan making all the noise.
Anyway, the point behind this "me too" reply is that it wasn't always this way. Perhaps there's a problem with the drivers introduced about a year ago?
It would be nice to hear some sort of reply from AMD on this subject. Hello?
A follow-up. Using the AMD utility I can see the temperature (green line) slowly rising and the fan speed (blue line) also steadily rising, but in reality the fan does not change speed at all. Finally when the GPU temperature hits 90 C, the fan kicks in briefly at ~4500 rpm, which quickly lowers the temperature and the supposed fan speed. There should be an uptick in the fan speed graph, but there isn't one.
My takeaway from this is that the AMD fan speed control is broken. It thinks it is steadily increasing the fan to deal with the heat, but the message is not going through. There must be a fail safe that kicks in when the GPU temperature gets too high, which causes the fan to run at max.