My laptop is a Dell Inspiron 3521, dual booted Windows 7 with Ubuntu 18.04 LTS.

Two days ago I installed Ubuntu, when I start Ubuntu the fan speed is at 0 RPM. It eventually increases when the temperature rises (1200 -> 2600 -> 3200 -> 4800). But the problem is that the fan speed goes to max (4800 RPM) at about 55 °C and it never decreases. The temperature drops to a minimum of 42 °C.

All readings are taken from lm-sensors and psensor. In Windows, at 42 °C the fan doesn't even start, and I've barely seen it goes to max speed (monitored with HWiNFO).

So I'm a bit worried about this matter. I've read some other articles about fan speeds, and as they suggest I don't want to mess with the fan speed by manually overriding it unless it's absolutely necessary. Laptop's specs are here.

  • What would be the cause to fan to run continuously at max speed?
  • Besides the sound, is it a problem to let fan continue at this speed?

Install i8kutils:

sudo apt install i8kutils

Next add to file /etc/modules the new line i8k:

echo "i8k" | sudo tee -a /etc/modules

Create and add to i8k.conf file new line options i8k force=1

echo "options i8k force=1" | sudo tee -a /etc/modprobe.d/i8k.conf

Now force i8k kernel module to load:

sudo modprobe i8k force=1

or just reboot your laptop.

Open file /etc/i8kmon.conf with nano text editor:

sudo nano /etc/i8kmon.conf

Add to the file the following strings:

# Run as daemon, override with --daemon option
set config(daemon)      0

# Automatic fan control, override with --auto option
set config(auto)        1

# Report status on stdout, override with --verbose option
set config(verbose) 1

# Status check timeout (seconds), override with --timeout option
set config(timeout) 20

# Temperature thresholds: {fan_speeds low_ac high_ac low_batt high_batt}
set config(0)   {{-1 0}  -1  40  -1  40}
set config(1)   {{-1 1}  30  60  30  60}
set config(2)   {{-1 2}  53  128  53  128}

# For computer with 2 fans, use a variant of this instead:
# Temperature thresholds: {fan_speeds low_ac high_ac low_batt high_batt}
# set config(0) {{-1 0}  -1  52  -1  65}
# set config(1) {{-1 1}  41  66  55  75}
# set config(2) {{-1 1}  55  80  65  85}
# set config(3) {{-1 2}  70 128  75 128}

# end of file

Now you can run i8kmon to check the cpu temperature and control the fan speed:


More information on i8kmon available from Ubuntu Manpage.

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