The following snippet from should work for some SuperMicro boards (X9/X10/X11): #set fan mode to 'full' Even though the thresholds are not directly available in the BIOS configuration screen in several cases this can then be set using IPMI.įreeBSD does have an IPMI driver and you can install sysutils/ipmitool to play with the settings. using ACPI) then the CPU and fans often runs at full throttle. When the server boots up the fans runs at BIOS default speeds until the OS takes over. This is however normally only available on serverclass motherboards with a BMC. If you have no luck going the ACPI route then maybe the Intelligent Platform Management Interface (IPMI) can be helpful to you. The sysctl hw.acpi will also show if any of the above settings can take effect. Performance_cpu_freq='1399' # Online CPU frequencyĮconomy_cx_lowest='C3' # Offline CPU idle stateĮconomy_cpu_freq='NONE' # Offline CPU frequency Performance_cx_lowest='C2' # Online CPU idle state Some BIOSes then adjust the fan speed accordingly (if within reasonable temperature range as well).Įxample setting in /etc/rc.conf powerd_enable='YES' So even if the fans are not directly exposed then you might be able to adjust them but adjusting the CPU frequency.

In FreeBSD this is handled by powerd which is disabled by default.

You can see if you have any settings related to fans using sysctl: # sysctl hw.acpiīut rather than manually tweaking the fan speed it should autoadjust according to temperature and load. Unfortunately most (if not all) modules are targetting laptops. If your hardware supports Advanced Configuration and Power Interface (ACPI) then there are loadable modules for ACPI support.

Bios fan speed control