The typical steps for fancontrol setup include:

• Running sensors-detect to ensure you have the correct modules and updates /etc/modules (/etc/sysconfig/lm_sensors on RH) to have the nct6775 entry.
• Running pwmconfig to test and configure each fan and creates the /etc/fancontrol file.

There are known issues where sometimes the hwmon ids change between boots, leaving your fans out of control. For that you would manually edit your /etc/fancontrol file to include the full path of each pwm and replace the id with [[:print:]]* like so: /sys/devices/platform/nct6775.656/hwmon/hwmon[[:print:]]*/pwm1

These are actual paths on the files system that you can browse to get an idea of what is available.

You may also need to edit /etc/sensors3.conf, I had to add some stuff for the ASUS Z97, I posted those details on this thread.

You may also need to add the following to the GRUB_CMDLINE_LINUX_DEFAULT variable in the /etc/default/grub file: acpi_enforce_resources=lax then rebuild the grub config grub-mkconfig -o /boot/grub/grub.cfg

I struggled with fan speed and thermal issues for a long time before I found tlp which has solved all my problems. You can learn more here:

TLP brings you the benefits of advanced power management for Linux without the need to understand every technical detail. TLP comes with a default configuration already optimized for battery life, so you may just install and forget it. Nevertheless TLP is highly customizable to fulfill your specific requirements.

Installation is the predictable

sudo apt install tlp

Configuration is automatic and I've never had to change it out of the box.

If tlp by itself doesn't solve all your thermal issues there are specific steps you can take for ASUS Laptops:

Kernel modules overview

• asus-nb-wmi is a kernel module, which is included in mainstream Linux kernel and is loaded automatically in 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. Blacklisting this module will prevent keyboard backlight to work.
• asus_fan is a kernel module, which allows to control both fans on some older Asus laptops. Does not work with the most recent models.

For myself after installing tlp I was able to remove a couple of fan control programs I had struggled to setup for my laptop. However I do not have an ASUS so you might need something more than just tlp.

I was having problems with Ubuntu 18.04 on my Asus laptop Q551L and high fan speed when coming out of sleep. My laptop had nvidia devices needing drivers including my video card GM108M GeForce 840M. Here's what fixed it for me as explained on this page.

$ ubuntu-drivers devices
$ sudo ubuntu-drivers autoinstall

Then reboot.

There can be two things at play here and for that there are two things you can do/try.

1. Check BIOS settings.

certain settings can be found/only be found in the BIOS, one of these settings that can be found in the BIOS are the fan settings, you can check here if there is something wrong there.

2. Sensor broke

It is possible that the sensor of the fan might have broken, i know there is away to check that with a GUI with Ubuntu and Windows so i will explain both.

Ubuntu

To check your sensor with Ubuntu you need to have hardinfo installed you do this by using the command sudo apt-get install hardinfo with this you can see if the sensor is okay or broken.

Windows

To check your sensor with Windows you will need to install Speedfan which can be found here. it will show you the temperatures your fansensors are reading and the speed of your fans

(side note: it has been a while since i used these programs so they might be different then i remember them)

i hope this will solve your problem cause it did for me

fan speed can be monitored from bios. try to change the settings there to "silent mode" in Q-fan configuration. to get there you can use this video: https://www.youtube.com/watch?v=8wMrCsFxLTQ&t=58s

I had the very same problem after replacing the motherboard. I finally found that I had forgotten to reconnect the sensor cable to the new motherboard. The sensor cable is small 4 pin plug. The socket for it is located on the right-front side of the board (looking at the front of the computer). It's very easy to overlook connecting it. My computer ran very quit as soon as the sensor was reconnected.

I had same problem with my Asus BM6820 desktop & Nvidia GeForce GT 730. I've tried all of the tips above but finally found. The problem was the kernel's stock Nvidia driver: nouveau caused the problem.

Boot your pc to init 3 runlevel to verify this problem. If the fan speed is OK, you can try to disable nvidia nouveau driver.

How to disable Nouveau nvidia driver:

https://linuxconfig.org/how-to-disable-nouveau-nvidia-driver-on-ubuntu-18-04-bionic-beaver-linux

$ sudo bash -c "echo blacklist nouveau > /etc/modprobe.d/blacklist-nvidia-nouveau.conf"
$ sudo bash -c "echo options nouveau modeset=0 >> /etc/modprobe.d/blacklist-nvidia-nouveau.conf"

Confirm the content of the new modprobe config file:

$ cat /etc/modprobe.d/blacklist-nvidia-nouveau.conf
blacklist nouveau
options nouveau modeset=0

Then install the proper Nvidia driver from Nvidia's site:

https://linuxconfig.org/how-to-install-the-nvidia-drivers-on-ubuntu-18-04-bionic-beaver-linux

My laptop was fairly new, and I wasn't running much with load of 2. With 8 CPU cores and an i7, I knew something was wrong.

I resolved this issue by using tlp .

lspci -v | perl -ne '/VGA/../^$/ and /VGA|Kern/ and print'
00:02.0 VGA compatible controller: Intel Corporation UHD Graphics 620 (rev 07) (prog-if 00 [VGA controller])
    Kernel driver in use: i915
    Kernel modules: i915

sudo add-apt-repository ppa:linrunner/tlp
sudo apt-get update

sudo apt-get install tlp tlp-rdw
systemctl enable tlp # to enable on startup
vim /etc/default/tlp

You should have something like this.

tlp-stat -c
--- TLP 1.2.2 --------------------------------------------

+++ Configured Settings: /etc/default/tlp
        TLP_ENABLE=1
        TLP_DEFAULT_MODE=AC
        TLP_PERSISTENT_DEFAULT=0
        DISK_IDLE_SECS_ON_AC=0
        DISK_IDLE_SECS_ON_BAT=2
        MAX_LOST_WORK_SECS_ON_AC=15
        MAX_LOST_WORK_SECS_ON_BAT=60
        CPU_HWP_ON_AC=balance_performance
        CPU_HWP_ON_BAT=balance_power
        CPU_MAX_PERF_ON_AC=100
        CPU_BOOST_ON_AC=1
        SCHED_POWERSAVE_ON_AC=0
        SCHED_POWERSAVE_ON_BAT=1
        NMI_WATCHDOG=0
        ENERGY_PERF_POLICY_ON_AC=performance
        ENERGY_PERF_POLICY_ON_BAT=power
        DISK_DEVICES="nvme0n1 sda"
        DISK_APM_LEVEL_ON_AC="254 254"
        DISK_APM_LEVEL_ON_BAT="128 128"
        SATA_LINKPWR_ON_AC="med_power_with_dipm max_performance"
        SATA_LINKPWR_ON_BAT="med_power_with_dipm min_power"
        AHCI_RUNTIME_PM_TIMEOUT=15
        WIFI_PWR_ON_AC=off
        WIFI_PWR_ON_BAT=on
        WOL_DISABLE=Y
        SOUND_POWER_SAVE_ON_AC=0
        SOUND_POWER_SAVE_ON_BAT=1
        SOUND_POWER_SAVE_CONTROLLER=Y
        BAY_POWEROFF_ON_AC=0
        BAY_POWEROFF_ON_BAT=0
        BAY_DEVICE="sr0"
        RUNTIME_PM_ON_AC=on
        RUNTIME_PM_ON_BAT=auto
        USB_AUTOSUSPEND=1
        USB_BLACKLIST_BTUSB=0
        USB_BLACKLIST_PHONE=0
        USB_BLACKLIST_PRINTER=1
        USB_BLACKLIST_WWAN=0
        RESTORE_DEVICE_STATE_ON_STARTUP=0
        NATACPI_ENABLE=1
        TPACPI_ENABLE=1
        TPSMAPI_ENABLE=1

In my case I use Intel, so I disabled Radeon. reboot, super annoying fan noise gone.

For me, It has been solved running the following:

sudo apt install smbios-utils
sudo smbios-thermal-ctl -v --set-thermal-mode=quiet

I had similar issues as @sef. I have a Lenovo laptop with Geforce MX150, running ubuntu 20. To fix my noisy fan I also had to:

$ ubuntu-drivers devices
$ sudo ubuntu-drivers autoinstall

but in addition I also had to go to "nvidia x server settings", and set "PRIME Profiles" to "NVIDIA on demand", reboot. If I now open "Thermal settings in the same program, I can see lower gpu temperatures. In the PowerMizer I can now see that performance level 0 is being used. I used to always be on a higher level (performance).