Check whether the fan is actually spinning at all (look at it). It could be a BIOS/driver bug which doesn't allow the card to report fan speeds below 20-27rpm. It may be reporting 20/27rpm because the fan is busted.
I've seen them do this in crossfire, the fan just stops spinning, which seems dumb, just heat soaks itself.
Please do as I said in overdrive.
Set GPU temp target of 85c and max fan speed of 70% then the card won't let itself turn into a radiator and keep itself cool.
Also try moving the black dip switch on the card, it could be that a feature of quiet mode is to turn the fan off, which is plain dumb on any graphics card.