I noticed that the old Mac Mini I reinstalled with Linux (a longer story involving the rEFInd Boot Manger) was running quite hot as soon as it got a bit busy. After installing and (auto-)configuring lm-sensors it turned out the fan was running at low speed despite the high temperatures.
I had at some point replaced the SSD I had in there (instead of the original SATA disk) with a different model. There's a temperature sensor glued to the front of the disk, which is a feed to the automatic fan speed management. The original disk (and the older SSD) had a metal casing, which acted as a heat transport to the sensor. The new SSD is enclosed in plastic instead, and while I put the sensor to the same position, it never measured the temperatures required to spin up the system fan.
For now, I ended up placing the sensor to the rear on top of the shielding of the Wifi module instead (the chipset heat sink didn't seem like a good idea). This seems to work well enough, and the fan now actually turns up when required:
I had at some point replaced the SSD I had in there (instead of the original SATA disk) with a different model. There's a temperature sensor glued to the front of the disk, which is a feed to the automatic fan speed management. The original disk (and the older SSD) had a metal casing, which acted as a heat transport to the sensor. The new SSD is enclosed in plastic instead, and while I put the sensor to the same position, it never measured the temperatures required to spin up the system fan.
For now, I ended up placing the sensor to the rear on top of the shielding of the Wifi module instead (the chipset heat sink didn't seem like a good idea). This seems to work well enough, and the fan now actually turns up when required:
$ sensors applesmc-isa-0300 Adapter: ISA adapter Master : 2424 RPM (min = 1500 RPM, max = 5500 RPM) TC0D: +46.2°C TC0H: +45.8°C TC0P: +47.0°C TH0P: +59.5°C TN0D: +68.8°C TN0P: +57.5°C TW0P: +56.5°C Tm0P: -128.0°C nouveau-pci-0200 Adapter: PCI adapter temp1: +68.0°C (high = +95.0°C, hyst = +3.0°C) (crit = +100.0°C, hyst = +2.0°C) (emerg = +135.0°C, hyst = +5.0°C) coretemp-isa-0000 Adapter: ISA adapter Core 0: +44.0°C (high = +105.0°C, crit = +105.0°C) Core 1: +46.0°C (high = +105.0°C, crit = +105.0°C)