375.10 GTX 1070 fan speed

Hi, i just got an Asus GTX 1070 STRIX. I have an issue in linux mint 18. (kernel 4.8.7) with drivers 375.10 beta.
When i play a game in linux, the fan speeds up as it gets warmer. But it will never spin down again, even after hours of just using the desktop. Only a reboot solves it, until i start something GPU demanding again.

I have enable coolbits 4, but i can only increase the fan speed in the control panel, but not decrease it.

Any suggestions?

How does your '1070’s fans behave when running Linux Mint 18’s stock kernel and the recommended nVidia driver for your card?

I did have this issue in windows 10 also. But i found the problem. Was a sata cable that got pushed into one of the fans when i had the case closed. So it was reporting 0rpm and spun the other fans to max rpm. ;-)