Hey everyone - Had the same problem as everyone. At first glance, the card seems perfect - quiet and ready to rip into a game - but when you start a game up, it goes all the way up to 100% fan speed and won't slow down until a reboot is done. When you go into GPU Tweak 2 it shows that the fans are at 0% and when you manually try to adjust them, they don't read and stay at 100% (as if the software doesn't talk to the fans and the card does what it wants and goes into Leaf Blower Mode).
I've read everyone's possible fixes - I've used DDU to remove drivers and reinstall, I've taken the card out and reseated it, I've used MSI Afterburner and set the fans to auto and to startup that way - nothing worked. Lastly, I did the hardware, I took one of my case fans and plugged it into the back of the card of the 1080 - my case fan was a 3 pin whereas the 1080 has 2-4 pins, it doesn't matter since I plugged the 3 pin into the 4 pin - and VOILA, after restarting my system the card now reads the GPU Fan Speed and I'm able to control it with no need for MSI Afterburner (unless I want it for manual overclocking). I've played one game with the setup this way and I've had no issues.
This took me a few hours - I'm a little unhappy that I have to sacrifice a fan in my case but we'll see how this works. I hope ASUS fixes this!!!!!!!!!!! I really didn't want to use the FanConnect in the back.