I recently got a NUC8i5BEK. The default fan settings seems a bit noisy so I decided to adjust it. What I've noticed is that the custom fan settings seem to be buggy. When I change any parameter from the built-in settings (e.g. decrease minimum duty cycle by 1%), the fan completely fails to response to CPU temperature changes. The fan speed does not ramp up even when the CPU temperature becomes very high (>80 C, reported by Intel Power Gadget). This problem does not exist when the built-in settings (balanced/cool/quiet) are used, so the fan itself is not faulty. I've also tried resetting the BIOS but it does not help.
This does not seem to be an isolated case. There are multiple posts reporting similar problems:
I noticed that the problem only exists when the primary temperature sensor is set to "Processor". If I set the primary temperature sensor to "PCH" (which is also in the same CPU package), the fan is able to respond to CPU temperature changes.
The other thing I noticed is that the BIOS doesn't display the CPU temperature (see picture). Instead, it shows "VR Temp", which I guess stands for Voltage Regulator Temperature. This seems really weird to me because the CPU temperature is arguably a more important statistic to show here. Does anyone know if it is by design, or could it be a bug?
One hypothesis I have is that there might be a bug in the BIOS. When using custom fan settings and the primary temperature sensor is set to "Processor", it is actually reading from the VR Temp sensor. As a result, the fan fails to respond to CPU temperature changes (the fan never ramps up because VR Temp is typically much lower than the CPU temperature).
Can someone from the NUC team look into this?
What a load of hooey. The CPU temperature *is* available and *could* be displayed by the BIOS. It is a bug, pure and simple. It is also a bug if the custom settings are not being implemented properly. I have seen it work and not work, so it is certainly inconsistent. Intel needs to fix these issues.