Lenovo ThinkCentre M920q - fan hysteresis option

Hi, guys.

Could someone help me with BIOS mo that can add some fan hysteresis option or just add few seconds delay for fan reaction to CPU temperatures change? In that machines fans whines very annoying when CPU temperature is changing very fast.

Thank you

@v.osypets - This and fan speeds etc, are usually EC FW controlled, which is not something you can easily change.
But, link me to your BIOS and I will see if there is fan speed option or not. If there is, that would be all there would be, at xx temp = xx fan speed, no hysteresis in BIOS usually, especially OEM BIOS
Redoing the thermal past on GPU and CPU heatsinks would probably help a lot, keep temps down much better with new/better than stock paste.


here is the link to the latest BIOS - https://support.lenovo.com/ua/en/downloads/ds503907. Repasting can’t help, because sometimes it just wining without any big temperatures spikes. Hysteresis will help in that case, but unfortunately many vendors don’t do that and it’s upsets…

thank you for your help

Oil the fans then maybe, or replace the one that is making noise? It may not be the fan/speeds, but rather the coils whining in PSU or in board around mosfet area etc. You can quite them if it’s this, but it would require you to put some clear silicon on top of them.
You can narrow down the noise location with board out of case, and use paper towel tube to your ear, move it around until you find the source of the noise.
Also, if it turns out that is is coil whine, sometimes enable/disable Speedstep, EIST, and S3 help with this.

YOu could also try sending email to Lenovo and ask them to send you special BIOS/EC update package to change the hysteresis, they may be helpful.
I checked the BIOS, and BIOS settings are only those like I mentioned (trip points and set fan speeds, and even these may not be what’s used here, if EC FW controls fans on this model)
You can look at all the settings on the BIOS side here with AMIBCP 5.02.0023 or 5.02.0031

You’re welcome, sorry this isn’t something we can adjust

@Lost_N_BIOS ,

Thank you for tips. It’s definitely CPU fan and it is just very fast reacting to CPU temperatures changes. So, EC FW can’t be tuned, right?

You’re welcome! Yes, sorry, there is no EC FW tools that are commonly known/working on various EC FW’s, it’s not easy to edit this without proper software.
And, you would need flash programmer to dump and edit this anyway. If you have a set, dump the EC FW chip and send to me, maybe I can find a tinker with something via blind hex poking around.

@Lost_N_BIOS ,

Thank you. I don’t have flash programmer, so I will try to create service request to Lenovo.


@Lost_N_BIOS ,

I found that there separate firmware for SuperIO and there are fan tables location. As I understand it’s part of EC firmware which is delivered as separate update module?

Here is the link for it - https://download.lenovo.com/pccbbs/think…/m1uct18usa.exe

Is there possible to do some changes?

@v.osypets - Yes, this is EC FW Update package, not sure if the included AFU will let you flash modified file, if we can even figure out what to modify.
I can already see it blocks the update if FW version is same as current, but we may be able to edit that check out. Did you already update to this? If not, don’t do it yet!
Please run eSIO_Flash.exe /d:origdump.bin << And send me this file

At what temp exactly does the fan change speeds, and what is idle speed before that and after? Please give me fan speed RPM and %, if you can.


I just decided to sell this device, so I think we can stop on this. Thank you for your sincere desire to help, I appreciate this!