When you are in BIOS Setup, all power management features and interrupts are disabled. This means that you could see higher-than-expected temperatures in this state and you cannot conclude whether anything is wrong.
I find that the supplied fan speed control configurations are nigh on to useless. I suggest that you use a customer configuration. Here is what I use:
Hope this helps,
Thanks, Scott, for your informative response. I set the fan settings to what you described, and the fan is quieter when system is idling in Windows 10. Just wish I could say the same when there's even a slight load on it.
Have you blown some air through the fan and cooling fins ?
After about six months of running, my NUC I7 needed it it. Solved the issue.