I've always wondered if these driver releases update firmware on the card itself, or set secret non-volatile settings.
I can only suggest trying the 15.9.1 beta.
Drivers don't update firmware on the videocard, that you have to do separately.
I've bin trying older Catalyst drivers yesterday, but with every driver it's the same problem : fan's will not go passed 28%
I think it's something in Windows that triggering this fan block reaction.
Using a custom fan profile now with Trixx and it works, it's just very annoying that for one reason or another the drivers and/or videocard doesn't respond like there suppose to.