After changing Plex containers from binhex-plex which stopped working after many years for me, to linuxserver-plex I noticed that my server's fans were constantly ramping up and staying at very loud minimum values even when nothing was going on. My fans had always been reported below here:

 

At 880rpm for every single fan. I know now it shows 450rpm average in the image below but NB! this is my NEW setting after following this guide.

 

 

Previously on the bottom bar all my fans also showed 880rpm (0%) average (again before my new changes following this guide).

 

 

I was also fine with that. The noise wasn't bothersome. My server is in the livingroom under my TV in the TV stand. I don't know how many decibels noisy it is in the livingroom but my fridge or air purifier generally makes the most noise. That said, the server was never "silent".

 

However, as I said the noise just got too much. Especially as my wife and I started sleeping in the living room on futons and converted our bedroom into a study in preparation for moving overseas. With the noise of the server now becoming a minor annoyance, it was suddenly made a lot worse with the constant fluctuations from Plex, Resilosync and qBittorrent. I finally took matters into my own hands.

 

How to properly use Fan Auto Control Plugin

Go to the Unraid Dashboard and scroll down to the bottom and press the "Gear" icon on the top right corner which you can see in the first image in this thread. It'll take you to this page:

 

 

What do these values mean?

 

• Enabled = Is the plugin turned on or off
• PWM controller = The detected controller which the plugin will use to control the fan voltage PWM
• Minimum PWM value = The lowest percentage of power that your fan can spin at without totally stalling
• Low Temperature Threshold (LTT) = The temperature at which your fans start spinning at the minimum PWM value
• High Temperature Threshold (HTT) = The temperature at which your fans will ramp up to 100%
• Refresh Interval (minutes) = How often do you want the controller to change the fan speed values based on temperature
• Exclude drives = Useful if you have one or more drives that are ALWAYS hot which will force the fans to always spin fast

 

Short example: Minimum PWM Value = 20, LTT = 40, HTT = 60 > Fan will spin at 20% max speed/power when temp within 1-2°C of the LTT which is 40°C. Between 40°C and 60°C the fan will increase in speed up to 100% at the HTT.

 

Enable the module and make sure the status on the far right in green is "Running"

 

1. Now for each of the fans listed that you have, click DETECT (the first DETECT button).

It takes about 10 seconds to finish, you should also pay attention to the bottom bar (second image in this thread) and notice that the requsite fan should temporarily spin up to 100% speed. That is, one of the fans (eg. the first one for pwm1) should show eg. 1280rpm (100%) temporarily.

 

2. Do this for every single fan. Do NOT press the other DETECT button for the "Minimum PWM value".

 

3. Now all of your fans are properly synced with the plugin.

 

4. The difficult and in my opinion unreliable way would now be to go through fans pwm1, pwm2 etc. and click the second DETECT button for Minimum PWM Value. However, this is really unreliable and YMMV depending on your fans, motherboard etc. It is better to just pick a value and be happy with it. This is also because the plugin may set your minimum value to something like 65% when your fan can actually go as low as 20%. The lowest value depends on the model and quality of your fan with better fans still being able to consistently spin with low PWM values. Noctua fans for example can generally do as low as 20% of their maximum PWM.

 

5. I recommend experimenting with 20(%) first. If you get a fan at the bottom bar that shows --- rpm then you have set either the PWM value too low that the fan isn't even starting, or your LOW Temperature Threshhold is too high. To test your fans you should take the current temperature eg. 39°C and 40°C in second image above. Then set the LTT to 1-2°C above this. As you can see. My current temps are 39°C and 40°C so my LTT should be 40°C. Then do this for every single fan. In the meantime set the high temperature threshhold to between 15-20°C above the LTT or at whatever temperature you want the fans to spin at full RPM at.

 

Keep the Refresh Interval at 5 minutes unless you want the fans changing all the time which is distracting.

Also I would keep exclude drives to None. Just leave it.

 

-----------------------------------------------------------

 

What is considered "silent"?

In my opinion under 30dBm (if possible). Essentially 400-500rpm should be otherwise inaudible over the sound of the rest of your machine and living environment, at least if you have mechanical HDDs. If you are using entirely silent SSDs and the only moving parts are your fans. Then you still shouldn't really be able to hear the fans from a distance of 1.5 metres (5ft) if they are spinning at around 400rpm. Most fans won't really be able to spin much slower either without risk of not even starting.

 

You can additionally set the LOW Temperature Threshold (LTT) to a higher number which will actually turn the fans OFF. For example. If I set 45°C as my LTT, then the fans won't even start up until my temps get to about 43.5-44°C. Bear in mind that your minimum temps with no fans can be quite high then so it's good to have them spinning even very slowly rather than not at all. Especially if you have mechanical drives as you will hear those anyway.

Edited March 26, 20251 yr by plantsandbinary

Thank you for this super comprehensive tutorial / how to for this plugin that can be tricky to fine tune.

 

i have 3 case fans connected to 2 pwm connectors (2x Front on Sys_Fan3/ 1x Rear at Sys_Fan1).
the plugin shows 5 pwm controllers. i guess one of them is the CPU_Fan which i want to be controlled by the motherboard.
Do you have a tipp for me how i can identify what's what?

Who can tell me which temperature sensor this plugin is using? Is it the CPU temp, the motherboard or the disks?

Hello!

Just curious which plugin this refers to. Looks great, but can't figure out which one to install!

Much thanks! :)

Hey, gotta kick in here as well!

I have an issue where not all my fans are displayed... The dashboard shows 3 fans only, which are:

GPU fan --> Intel Arc A310

CPU fan

One of my chassis-fans.

On my motherboard (ASUS TUF B360M-Plus Gaming) I have three fan-headers:

CPU_FAN - Connected to the CPU-fan

CHA_FAN1 - Connected to rear exhaust fans
CHA_FAN2 - Connected to the front intake fans

I believe it's the CHA_FAN2 that is NOT detected for some reason.

I'm also experimenting with FANCTRL PLUS as an alternative. THAT plugin recognizes all the fan-headers on my motherboard, but NOT the GPU-fan!

This is driving me nuts, would like to have ALL fans recognized in the same plugin on the Dashboard!

And yes, I've gone through the detection-process in both plug-ins several times without success...

Any ideas?

And by the way, just like @gotomato the plugin recognizes 6 fan-controllers on the settings-page
nct6796 - PWM1

nct6796 - PWM2

nct6796 - PWM3

nct6796 - PWM4

nct6796 - PWM5

nct6796 - PWM7

NO, there is NO nct6796 - PWM6! :)

Edited August 28, 2025Aug 28 by Prebz

For all the people who struggled in identifying the PWM number, I suggest to do the following:

take note of this part of the string, this identifies the base address of your PWM fans:

So in my case I copied the base address: /sys/devices/platform/nct6775.656/hwmon/hwmon4/

Now from terminal I can try to set each fan (one by one) at 100% of the power to see which fan react to the PWM number.

This for example for PWM controller #2:

# Now we're going to set PWM control to manual

echo 1 > /sys/devices/platform/nct6775.656/hwmon/hwmon4/pwm2_enable

# Then now we're setting it to max power to identify which fan in the case react to PWM 2 controller

echo 255 > /sys/devices/platform/nct6775.656/hwmon/hwmon4/pwm2

# finally once PWM 2 controller has been identified, we can set the fan back to PWM mode to auto

echo 5 > /sys/devices/platform/nct6775.656/hwmon/hwmon4/pwm2_enable

Now you can repeat the process, just change pwm2 with the next one you wanna test and so on until when you'll have tested all...

Of course you can use this technique also to identify manually the minimum PWM value, once you've set the PWM mode to manual, just use the second command to vary the PWM value from 0 to 255 and choose the value you prefer.

Sometimes I saw that after changing the values and saving them in the plugin it was a total mess even if I was sure 100% I did everything properly, but then everything got fixed after a server reboot.

Hi all,

Since my update to Unraid 7.2.7 I noticed that one of my two fans controlled by PWM, namely pwm3, is no longer working.

I tried to force it with echo 1 > /sys/class/hwmon/hwmon4/pwm3_enable but the value keep reading 0.

Am I the only one to see that behavior?

Gemini told me to add the linux kernel parameter acpi_enforce_resources=lax , is this a possible solution?

Quick update: after changing my BIOS PWM settings from "automatic" to "software" now I have somewhat recover the control on both of my two fan. Somewhat because the fan that was previously not working is now stuck at 100%. Whatever I set as minimum PWM value in fan auto control is not reflected in the /sys/class/.../pwm3 which always read 255.

I guess for now that will do, for sure full blast is better than nothing.

I have a problem with Dynamix Auto Fan Control

Fans are set to full speed and pwm control in BIOS (so it is fully handled via software) and then I can control them via terminal. When I enable the plugin it detects the fans and it controls them but, the fans are always off.

The plugin is detecting 0ºC for all the drives

grep -i autofan /var/log/syslog

Jun 12 01:51:08 server autofan: Highest disk temp is 0C, adjusting fan speed from: FULL (100% @ 1577rpm) to: OFF (0% @ 602rpm)
Jun 12 01:51:08 server autofan: Highest disk temp is 0C, adjusting fan speed from: FULL (100% @ 1925rpm) to: OFF (0% @ 565rpm)
Jun 12 01:51:08 server autofan: Highest disk temp is 0C, adjusting fan speed from: FULL (100% @ 0rpm) to: OFF (0% @ 0rpm)
Jun 12 01:51:43 server autofan: killing autofan process 90699
Jun 12 01:51:53 server autofan: killing autofan process 90735
Jun 12 01:51:58 server autofan: killing autofan process 90791
Jun 12 01:52:04 server ool www[79948]: /usr/local/emhttp/plugins/dynamix.system.autofan/scripts/rc.autofan 'start'
Jun 12 01:52:04 server autofan: autofan process ID 94465 started, To terminate it, type: autofan -q -c /sys/devices/platform/nct6775.672/hwmon/hwmon5/pwm1 -f /sys/devices/platform/nct6775.672/hwmon/hwmon5/fan1_input
Jun 12 01:52:04 server autofan: autofan excluding drives nvme0n1,nvme1n1 from max temp calculations
Jun 12 01:52:04 server autofan: autofan process ID 94501 started, To terminate it, type: autofan -q -c /sys/devices/platform/nct6775.672/hwmon/hwmon5/pwm4 -f /sys/devices/platform/nct6775.672/hwmon/hwmon5/fan4_input
Jun 12 01:52:04 server autofan: autofan excluding drives nvme0n1,nvme1n1 from max temp calculations
Jun 12 01:52:04 server autofan: autofan process ID 94557 started, To terminate it, type: autofan -q -c /sys/devices/platform/nct6775.672/hwmon/hwmon5/pwm5 -f /sys/devices/platform/nct6775.672/hwmon/hwmon5/fan5_input
Jun 12 01:52:04 server autofan: autofan excluding drives nvme0n1,nvme1n1 from max temp calculations
Jun 12 01:52:09 server autofan: Highest disk temp is 0C, adjusting fan speed from: FULL (100% @ 1925rpm) to: OFF (0% @ 540rpm)
Jun 12 01:52:09 server autofan: Highest disk temp is 0C, adjusting fan speed from: FULL (100% @ 1228rpm) to: OFF (0% @ 569rpm)
Jun 12 01:52:09 server autofan: Highest disk temp is 0C, adjusting fan speed from: FULL (100% @ 0rpm) to: OFF (0% @ 0rpm)
Jun 12 01:58:02 server autofan: killing autofan process 94465
Jun 12 01:58:12 server autofan: killing autofan process 94501
Jun 12 01:58:17 server autofan: killing autofan process 94557

Fan 1-4-5 are the front fans, the ones that I want to control the drive temperature. And they are idle no matter what so I had to disable the plugin.

cat /var/local/emhttp/disks.ini | grep temp

temp="50"
temp="47"
temp="51"
temp="53"
temp="52"
temp="48"
temp="50"
temp="51"
temp="49"
temp="48"
temp="53"
temp="50"
temp="51"
temp="50"
temp="43"
temp="43"
temp="43"
temp="43"

The drives are reporting the correct temperature.

Here's a screenshot of a fan configuration (had to disable it else my drives would burn).

Edited June 12Jun 12 by Zotarios
clarify BIOS settings