Fan speed control

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Fan control can bring various benefits to your system, such as quieter working system and power saving by completely stopping fans on low CPU load.

Warning: Configuring or completely stopping fans on high system load might result in permanently damaged hardware.


Note: Laptop users should be aware about how cooling system works in their hardware. Some laptops have single fan for both CPU and GPU and cools both at the same time. Some laptops have two fans for CPU and GPU, but the first fan cools down CPU and GPU at the same time, while the other one cools CPU only. In some cases, you will not be able to use Fancontrol script due to incompatible cooling architecture (e.g. one fan for both GPU and CPU). Here is some more information about this topic.

There are multiple working solutions for fan control for both desktops and notebooks. Depending on your needs:

Fancontrol (lm-sensors)

fancontrol is a part of lm_sensors, which can be used to control the speed of CPU/case fans.

Support for newer motherboards may not yet be in the Linux kernel. Check the official lm-sensors devices table to see if experimental drivers are available for such motherboards.


The first thing to do is to run

# sensors-detect

This will detect all of the sensors present and they will be used for fancontrol. After that, run the following to check if it detected the sensors correctly:

$ sensors
Adapter: ISA adapter
Core 0:      +29.0°C  (high = +76.0°C, crit = +100.0°C)  
Adapter: ISA adapter
Vcc:         +1.14 V  (min =  +0.00 V, max =  +4.08 V)   
VTT:         +2.08 V  (min =  +0.00 V, max =  +4.08 V)   
+3.3V:       +3.33 V  (min =  +0.00 V, max =  +4.08 V)   
NB Vcore:    +0.03 V  (min =  +0.00 V, max =  +4.08 V)   
VDRAM:       +2.13 V  (min =  +0.00 V, max =  +4.08 V)   
fan1:        690 RPM  (min =   10 RPM)
temp1:       +37.5°C  (low  = +129.5°C, high = +129.5°C)  sensor = thermistor
temp2:       +25.0°C  (low  = +127.0°C, high = +127.0°C)  sensor = thermal diode
Note: If the output does not display an RPM value for the CPU fan, one may need to #Increase the fan divisor for sensors. If the fan speed is shown and higher than 0, this is fine.


Once the sensors are properly configured, use pwmconfig to test and configure fan speed control. Following the guide should create /etc/fancontrol a customized configuration file. In the guide, the default answers are in parenthesis if you press enter without typing anything. Enter "y" for yes, "n" for no.

# pwmconfig
Note: Some users may experience issues when using /sys/class/hwmon/ paths for their configuration file. hwmon class device symlinks points to the absolute paths, and are used to group all of the hwmon sensors together into one folder for easier access. Sometimes, the order of the hwmon devices change from a reboot, causing fancontrol to stop working. Go to #Device Paths have Changed in /etc/fancontrol for more information on how to fix this.


Some users may want to manually tweak the config file after running pwmconfig, usually to fix something. For manually tweaking the /etc/fancontrol configuration file, see the fancontrol(8) manual page for the definitions of the variables.

Users will probably encounter the hwmon path issues as noted above in #Fancontrol (lm-sensors). Look at #Device Paths have Changed in /etc/fancontrol for more information.

Tip: Use MAXPWM and MINPWM options that limit fan speed range. See the fancontrol(8) manual page for details.
Note: Temperature and fan sensor paths could change as well (usually on a kernel update) (e.g. hwmon0/device/temp1_input becomes hwmon0/temp1_input). Check the system log to find out which path is the troublemaker:
# systemctl status fancontrol.service 
and correct your config file accordingly.

Running Fancontrol

Try to run fancontrol:

# fancontrol

A properly configured setup will not output errors and will take control of the system fans. Users should hear system fans starting shortly after executing this command.

To enable starting fancontrol automatically on every boot, enable fancontrol.service:

# systemctl enable fancontrol.service

To start it in the background, run

# systemctl start fancontrol.service

For an unofficial GUI install fancontrol-guiAUR or fancontrol-kcmAUR.

Fancontrol stops working after suspend–wake cycles

Unfortunately, fancontrol does not work after suspending. As per the filed bug, you will have to restart fancontrol after suspending. This can be achieved automatically by a systemd hook.


NBFC is a cross-platform fan control solution for notebooks. It comes with a powerful configuration system, which allows to adjust it to many different notebook models, including some of the latest ones.


NBFC can be installed as nbfcAUR or nbfc-gitAUR. Also start and enable nbfc.service.


NBFC comes with pre-made profiles. You can find them in /opt/nbfc/Configs/ directory. When applying them, use exact profile name without extension (e.g. some profile.xml becomes "some profile").

Check if there is anything NBFC can recommend:

$ nbfc config -r

If there is at least one model, try to apply this profile and see how fan speeds are being handled. For example:

$ nbfc config -a "Asus Zenbook UX430UA"
Note: If you are getting File Descriptor does not support writing, delete StagWare.Plugins.ECSysLinux.dll [1] and restart nbfc.service:
# mv /opt/nbfc/Plugins/StagWare.Plugins.ECSysLinux.dll /opt/nbfc/Plugins/StagWare.Plugins.ECSysLinux.dll.old

If above solution did not help, try appending ec_sys.write_support=1 to kernel parameters.

If there are no recommended models, go to NBFC git repository or /opt/nbfc/Configs/ and check if there are any similar models available from the same manufacturer. For example, on Asus Zenbook UX430UQ, the configuration Asus Zenbook UX430UA did not work well (fans completelly stopped all the time), but Asus Zenbook UX410UQ worked fantastically.

Run nbfc to see all options. More information about configuration is available at upstream wiki.

Dell laptops

i8kutils is a daemon to configure fan speed according to CPU temperatures on some Dell Inspiron and Latitude laptops. It uses the /proc/i8k interface provided by the dell_smm_hwmon driver (formerly i8k). Results will vary depending on the exact model of laptop.

Warning: i8kutils BIOS system calls stop the kernel for a moment on some systems (confirmed on Dell 9560), this can lead to side effects like audio dropouts, see


i8kutilsAUR is the main package to control fan speed. Additionally, you might want to install these:

  • acpi - must be installed to use i8kmon.
  • tcl - must be installed in order to run i8kmon as a background service (using the --daemon option).
  • tk - must be installed together with tcl to run as X11 desktop applet.
  • dell-bios-fan-control-gitAUR - recommended if your BIOS overrides fan control


By default, i8kmon only monitors the CPU temperature and fan speed passively. To enable its fan speed control, either run it with the --auto option or enable the option permanently in /etc/i8kutils/i8kmon.conf:

set config(auto)       1

The temperature points at which the fan changes speed can be adjusted in the same configuration file. Only three fans speeds are supported (high, low, and off). Look for a section similar to the following:

set config(0)  {{0 0}  -1  55  -1  55}
set config(1)  {{1 1}  45  75  45  75}
set config(2)  {{2 2}  65 128  65 128}

This example starts the fan at low speed when the CPU temperature reaches 55 °C, switching to high speed at 75 °C. The fan will switch back to low speed once the temperature drops to 65 °C, and turns off completely at 45 °C.

Installation as a service

i8kmon can be started automatically as a systemd service:

 # systemctl enable i8kmon
 # systemctl start i8kmon

BIOS overriding fan control

Some newer laptops have BIOS fan control in place which will override the OS level fan control. To test if this the case, run i8kmon with verbose mode in a command line, make sure the CPU is idle, then see if the fan is turned off or turned down accordingly.

If the BIOS fan control is in place, you can try using dell-bios-fan-control-gitAUR:

Warning: turning off BIOS fan control could result in damage to your hardware. Make sure you have i8kmon properly set up beforehand, or leave the CPU idle while you test this program

To enable BIOS fan control:

 # dell-bios-fan-control 1

To disable BIOS fan control:

 # dell-bios-fan-control 0

To automatically disable BIOS fan control via systemd:

 # systemctl enable dell-bios-fan-control
 # systemctl start dell-bios-fan-control

ThinkPad laptops

Current fan control daemons available in the AUR are simpfand-gitAUR and thinkfanAUR (recommended).


Install thinkfanAUR or thinkfan-gitAUR. Optionally, but recommended, install lm_sensors. Then have a look at the files:

# pacman -Ql thinkfan

Note that the thinkfan package installs /usr/lib/modprobe.d/thinkpad_acpi.conf, which contains

options thinkpad_acpi fan_control=1

So fan control is enabled by default.

Now, load the module:

# modprobe thinkpad_acpi
# cat /proc/acpi/ibm/fan

You should see that the fan level is "auto" by default, but you can echo a level command to the same file to control the fan speed manually:

# echo level 1 > /proc/acpi/ibm/fan
Fan Levels
Level Effect
0 off
2 low speed
4 medium speed
7 maximum speed
auto default - automatic
full-speed maximum speed

The thinkfan daemon will do this automatically.

Finally, enable the thinkfan.service.

To configure the temperature thresholds, you will need to copy one of the example config files (e.g. /usr/share/doc/thinkfan/examples/thinkfan.conf.simple) to /etc/thinkfan.conf, and modify to taste. This file specifies which sensors to read, and which interface to use to control the fan. Some systems have /proc/acpi/ibm/fan and /proc/acpi/ibm/thermal available; on others, you will need to specify something like:

hwmon /sys/devices/virtual/thermal/thermal_zone0/temp

to use generic hwmon sensors instead of thinkpad-specific ones.


You can test your configuration first by running thinkfan manually (as root):

# thinkfan -n

and see how it reacts to the load level of whatever other programs you have running.

When you have it configured correctly, start/enable thinkfan.service.

Asus laptops

This topic will cover drivers configuration on Asus laptops for Fancontrol (lm-sensors).

Kernel modules

In configuration files, we are going to use full paths to sysfs files (e.g. /sys/devices/platform/asus-nb-wmi/hwmon/hwmon[[:print:]]*/pwm1). This is because hwmon1 might change to any other number after reboot. Fancontrol (lm-sensors) is written in Bash, so using these paths in configuration file is completely acceptable. You can find complete /etc/fancontrol configuration file examples at ASUS N550JV#Fan control.


asus-nb-wmi is a kernel module, which is included in the Linux kernel and is loaded automatically on Asus laptops. It will only allow to control a single fan and if there is a second fan you will not have any controls over it. Note that blacklisting this module will prevent keyboard backlight to work.

Below are the commands to control it. Check if you have any controls over your fan:

# echo 255 > /sys/devices/platform/asus-nb-wmi/hwmon/hwmon[[:print:]]*/pwm1           # Full fan speed (Value: 255)
# echo 0 > /sys/devices/platform/asus-nb-wmi/hwmon/hwmon[[:print:]]*/pwm1             # Fan is stopped (Value: 0)
# echo 2 > /sys/devices/platform/asus-nb-wmi/hwmon/hwmon[[[:print:]]*/pwm1_enable     # Change fan mode to automatic
# echo 1 > /sys/devices/platform/asus-nb-wmi/hwmon/hwmon[[:print:]]*/pwm1_enable      # Change fan mode to manual

If you were able to modify fan speed with above commands, then continue with #Generate config file with pwmconfig.


asus_fan is a kernel module, which allows to control both fans on some older Asus laptops. It does not work with the most recent models.

Install the DKMS asus-fan-dkms-gitAUR kernel module, providing asus_fan:

# modprobe asus_fan

Check if you have any control over both fans:

# echo 255 > /sys/devices/platform/asus_fan/hwmon/hwmon[[:print:]]*/pwm1          # Full CPU fan speed (Value: 255)
# echo 0 > /sys/devices/platform/asus_fan/hwmon/hwmon[[:print:]]*/pwm1            # CPU fan is stopped (Value: 0)
# echo 255 > /sys/devices/platform/asus_fan/hwmon/hwmon[[:print:]]*/pwm2          # Full GFX fan speed (Value: 255)
# echo 0 > /sys/devices/platform/asus_fan/hwmon/hwmon[[:print:]]*/pwm2            # GFX fan is stopped (Value: 0)
# echo 2 > /sys/devices/platform/asus_fan/hwmon/hwmon[[:print:]]*/pwm1_enable     # Change CPU fan mode to automatic
# echo 1 > /sys/devices/platform/asus_fan/hwmon/hwmon[[:print:]]*/pwm1_enable     # Change CPU fan mode to manual
# echo 2 > /sys/devices/platform/asus_fan/hwmon/hwmon[[:print:]]*/pwm2_enable     # Change GFX fan mode to automatic
# echo 1 > /sys/devices/platform/asus_fan/hwmon/hwmon[[:print:]]*/pwm2_enable     # Change GFX fan mode to manual
# cat /sys/devices/platform/asus_fan/hwmon/hwmon[[:print:]]*/temp1_input          # Display GFX temperature (will always be 0 when GFX is disabled/unused)

If everything works, you might want to load this kernel module on boot:


Continue with #Generate config file with pwmconfig.

Generate config file with pwmconfig

If you get an error There are no working fan sensors, all readings are 0 while generating config file with pwmconfig, open first console and execute:

# watch -n 1 "echo 2 > /sys/devices/platform/<kernel_module>/hwmon/hwmon[[:print:]]*/pwm1_enable"

If you use asus_fan kernel module and have 2nd fan, in second console:

# watch -n 1 "echo 2 > /sys/devices/platform/<kernel_module>/hwmon/hwmon[[:print:]]*/pwm2_enable"

And finally, in the third console:

# pwmconfig

Once you are done and the configuration file is generated, you should stop the first and second consoles. Continue with Fancontrol (lm-sensors). After config file is generated, you might need to manually replace PWM values with full sysfs paths as they are used in these steps, because hwmon number values might change after reboot.

AMDGPU sysfs fan control

AMDGPU kernel driver offers fan control for graphics cards via hwmon in sysfs.

Configuration of manual control

To switch to manual fan control from automatic, run

# echo "1" > /sys/class/drm/card0/device/hwmon/hwmon0/pwm1_enable

Set up fan speed to e.g. 50% (100% are 255 PWM cycles, thus calculate desired fan speed percentage by multiplying its value by 2.55):

# echo "128" > /sys/class/drm/card0/device/hwmon/hwmon0/pwm1

To reset to automatic fan control, run

# echo "2" > /sys/class/drm/card0/device/hwmon/hwmon0/pwm1_enable
Warning: Resetting fan speed to auto may not work due to a driver bug and instead a restart of the driver may be required as a workaround.


The amdgpu-fanAUR package is an automated fan controller for AMDGPU-enabled video cards written in Python. It uses a "speed-matrix" to match the frequency of the fans with the temperature of the GPU, for example:

speed_matrix:  # -[temp(*C), speed(0-100%)]
- [0, 0]
- [40, 30]
- [60, 50]
- [80, 100]

Once the package is installed, it can be run as a service, so you can either run it for the current session:

# systemctl start amdgpu-fan.service

or executed at boot

# systemctl enable amdgpu-fan.service

fancurve script

Not just fan controls are offered via hwmon in sysfs, but also GPU temperature reading:

cat /sys/class/drm/card0/device/hwmon/hwmon0/temp1_input

This outputs GPU temperature in °C + three zeroes, e.g. 33000 for 33°C.

The bash script amdgpu-fancontrol by grmat offers a fully automatic fan control by using the described sysfs hwmon functionality. It also allows to comfortably adjust the fancurve's temperature/PWM cycles assignments and a hysteresis by offering abstracted configuration fields at the top of the script.

Tip: In order to function correctly, the script needs at least three defined temperature/PWM cycles assignments.

For safety reasons, the script sets fan control again to auto when shutting down. This may cause spinning up of fans, which can be worked around at cost of security by setting set_fanmode 1 in the section function reset_on_fail.

Setting up fancurve script

To start the script, it is recommend to do so via systemd init system. This way the script's verbose output can be read via journalctl/systemctl status. For this purpose, a .service configuration file is already included in the GitHub repository.

It may also be required to restart the script via a root-resume.service after hibernation in order to make it automatically function properly again:

Description=Local system resume actions

ExecStart=/usr/bin/systemctl restart amdgpu-fancontrol.service



Increase the fan divisor for sensors

If sensors does not output the CPU fan RPM, it may be necessary to change the fan divisor.

The first line of the sensors output is the chipset used by the motherboard for readings of temperatures and voltages.

Create a file in /etc/sensors.d/:

chip "coretemp-isa-*"
set fanX_div 4

Replacing coretemp-isa- with name of the chipset and X with the number of the CPU fan to change.

Save the file, and run as root:

# sensors -s

which will reload the configuration files.

Run sensors again, and check if there is an RPM readout. If not, increase the divisor to 8, 16, or 32. YMMV!

Device Paths have Changed in /etc/fancontrol

The enumerated hwmon symlinks located in /sys/class/hwmon/ might vary in order because the kernel modules do not load in a consistent order per boot. Because of this, it may cause fancontrol to not function correctly.


In /etc/conf.d/lm_sensors, there are 2 arrays that lists all of the modules detected when you execute sensors-detect. These get loaded in by fancontrol. If the file does not exist, run sensors-detect as root, accepting the defaults. Open (or create) /etc/modules-load.d/modules.conf. Get all of the modules listed from the 2 variables in /etc/conf.d/lm_sensors/ and place them into the /etc/modules-load.d/modules.conf file, one module per line. Specifying them like this should make a defined order for the modules to load in, which should make the hwmon paths stay where they are and not change orders for every boot. If this doesnt work, I highly recommend finding another program to control your fans. If you cannot find any, then you could try using the alternative solution below.

Alternative Solution: Absolute paths

Using absolute file paths in fancontrol does not work by default, as its helper script pwmconfig is programmed to only use the hwmon paths to get the files. The way it does this is that it detects whether the hwmon path that is provided in its config file /etc/fancontrol did not change, and uses the variables DEVNAME and DEVPATH to determine such change. If your hwmon paths keep changing, this will prevent fancontrol from running no matter what you do. However, one can circumvent this problem. Open /usr/bin/fancontrol, and comment out this part of the script:

if ! ValidateDevices "$DEVPATH" "$DEVNAME"
     echo "Configuration appears to be outdated, please run pwmconfig again" >&2
     exit 1
Note: Doing this may make fancontrol write into files you gave it in the config file, no matter what the file is. This can corrupt files if you provide the wrong path. Be sure that you are using the correct path for your files.

Another thing to note is that while doing this workaround, using pwmconfig to create your script again will overwrite all of your absolute paths that you have configured. Therefore, it is better to manually change the old paths to the new paths if it is needed instead of using pwmconfig.

Commenting this out should effectively ignore the hwmon validation checks. You can also ignore the variables DEVNAME and DEVPATH in the config file as well. After this, replace all of the hwmon paths in the other variables with its absolute path. To make it easier, rerun pwmconfig to refresh the hwmon devices. The hwmon paths in the config file should now point to the correct absolute paths. For each hwmon path, run the following command:

"#" is the enumeration of the hwmon path
$ readlink -f /sys/class/hwmon/hwmon#/device

This will give you the absolute path of the device.

For example, a /etc/fancontrol file lists FCTEMPS as this:


Executing readlink -f /sys/class/hwmon/hwmon3/device can, for example, output /sys/devices/platform/coretemp.0/. cd into this directory. If you see a /hwmon/hwmon#/ directory, you have to do this in your fancontrol config file to replace the hwmon# path. From the previous example:


Essentially, you must replace the hwmon path with the absolute path, concatenated with {{ic|/hwmon/[[:print:]]*/} so that bash can catch the random enumerated hwmon name.

If you do not see the /hwmon/hwmon#/ directory, then you do not have to worry about this. This means that the temperature files are in the root of the device folder. Just replace hwmon#/ with the absolute file path. For example:


After replacing all of paths, fancontrol should work fine.