Fan is pulsating after Bios-Update

[Hans1232]

Hi, i have the following problem.

My Elitebook 840 G5, I bought it early 2019, worked well until Windows-10 initialised an bios-update in late 2021.

Ist was the first Bios-Update on this device and since this day, the fan ist pulsating if they run slow to medium speed. On higher speed,

the fan run constantly, no pulsating. The pulsation is characterized by speed up an down like a sinus curve.

In idle, the fan runs so slow that the pulsation is not perceptible. But when working, the constant change in the speed 
of the fan is very noticeable.

My first try to fix the issue was to reset the bios to the previous version.  But the system forbade me the bios-reset to the previous version.
Next, i tried to fix it by updating the bios. But until today no bios-update helped. Also no available firmware-update.

I hope, anyone have an idea to help me.

[ub6424]

Hello @Hans1232 

Sorry to hear that you are having problems ... and I would like to help you.

(1) Update BIOS

HP Firmware Pack (Q78)

01.20.00 Rev.A

16.3 MB

May 10, 2022

Download

Why should you install the update ?

https://support.hp.com/us-en/document/ish_4123786-2338478-16

Quote: "

Updating the BIOS is recommended as standard maintenance of the computer. It can also help resolve the following issues:

• An available BIOS update resolves a specific issue or improves computer performance.
• The current BIOS does not support a hardware component or a Windows upgrade.
• HP Support recommends installing a specific BIOS update.

"

(2) Reboot

(3) Install/Update

Intel Chipset Installation Utility

10.1.18243.8188 Rev.S

3.0 MB

Jan 3, 2020

Download

Intel Dynamic Platform and Thermal Framework Driver

8.5.10103.7263 Rev.A

8.2 MB

Feb 26, 2019

Download

Intel Management Engine Driver

2205.15.0.2623 Rev.W

272.4 MB

Apr 18, 2022

Download

Intel Sensor Hub Components Driver

3.10.100.4101 Rev.A

3.4 MB

Sep 30, 2019

Download

Intel Serial IO Driver

30.100.1914.3 Rev.A

2.8 MB

Jun 10, 2019

Download

Intel Management Engine Firmware

11.8.92.4222 Rev.A

11.6 MB

Apr 18, 2022

Download

(4) Reboot

(5) Test again ...

[Hans1232]

Thanks for your answer @Ub6424.

But sadly, the issue is still present.

[ub6424]

Try

(1) NoteBook FanControl

https://github.com/hirschmann/nbfc

See <Getting started>

Releases

https://github.com/hirschmann/nbfc/releases

Direct Download ( latest stable )

Download here -> https://github.com/hirschmann/nbfc/releases/download/1.6.3/NoteBookFanControl.1.6.3.setup.exe

NoteBook FanControl Config: ( Should also work with Elitebook 840 G5 )

Download here -> HP EliteBook 840 G2 ( Right click > Save link as )

Example screenshot:

(functions and appearance may vary slightly depending on the version used)

(2) Please report your results

[Hans1232]

Ok,

in range of 0% to 17,5% of fanspeed, the fan ist pulsating.

From 20% and higher, it works fine. (manual fan control)

In auto-mode, the fan pulsating up to 50% of fanspeed. In this range,

the fanspeed fluctuating frequently up to 5% to the targetspeed.

The same fluctuation can i see in manual mode. (0% to 17,5% of fanspeed)

At idle, the cpu temp is stable on 43 °C and at load it grows up to 78 °C.

There are no noticeable fluctuations in cpu temp. And I can't detect cpu throttling.

[ub6424]

Check and set bios settings: fan <always on>, this should help additionally.

Wait for the next bios update. Until then, you can live with the fan control variant.

This should be the temporary solution to the problem