I've noticed that if I reboot while the fan is spinning like mad for no reason, slowly the fan slows down and stops. But then right on time, after about 4 minutes 45 seconds of windows uptime, it starts to ramp up again.
Another observation, it happens in safe mode too.
I'm getting pretty sick of bumping my own thread constantly but maybe this will be helpful to someone, or someone with a solution will finally show up, or maybe someone from asus will chime in eventually... huh?