Question Will CPU turbo increase fan speed?

[Craig C]

When the CPU turbos and temps increase, will the BIOS or OS increase fan/pump speed accordingly?
I'm looking for a higher-end Z390 Asus or Gigabyte board (Maximus Hero, Aorus Xtreme...), with an i9-9900.
I'll be using Linux, so I'll need to know if its the BIOS/UEFI or OS that handles this feedback loop. Does anyone know which kernel module?

 

[kschendel]

Your best bet is probably to set up a fan curve in the BIOS. Linux has a fancontrol service that depends on sensor input (via /sys/class/hwmon/hwmonxx) with the hwmon data being fed by a kernel module specific to the hardware. I don't have an Intel CPU so I'm not sure exactly what module would be used. Regardless, the fancontrol stuff is a bit hokey (it's timer driven, for starters) and you're much better off IMO with a BIOS defined fan curve.

 

[Craig C]

So does Linux access the BIOS after boot? I thought it doesnt.

 

[kschendel]

So does Linux access the BIOS after boot? I thought it doesnt.

Not sure what you mean. If you set up a BIOS fan curve, the BIOS runs the fans when linux is running, as long as the corresponding hwmon inputs are left at auto which is the initial state. The fancontrol service pokes the hwmon inputs for the specified fans to manual control and then reads temperature sensors and writes PWM values to control the fans; it's a bit clunky and I'd only use fancontrol.service if there were no other way to control a fan. (e.g. on my box, the GPU fan is run via fancontrol.service, the case and CPU cooler fans are run via BIOS curves.)

 

[BonzaiDuck]

Without trying too much else, yet the experience of having boards of different manufacture over the years, I cling to my dated conclusion that ASUS offers some of the better fan control options. It was always a positive feature when I had to select a new board for a new system.

The BIOS fan setup is darn good and good enough that you shouldn't need any fan-control software running in the OS. Forget about Speedfan. YOu should be able to set the fan curves in the BIOS, and it then just becomes a matter of temperature thresholds increasing or decreasing the fan(s) speed(s). With my now-dated Sabertooth Z170 S board for this system I built in 2016, as with earlier boards like my Z68's, ASUS provides plugs which will utilize either 3-pin voltage control or 4-pin PWM, and the BIOS is mode-selectable for those plugs in the fan-control sub-menus.

 

[Craig C]

@kschendel & @BonzaiDuck: Excellent information; the less I have to install, the better.