Question Strange fan behaviour on ASRock B460M-ITX/ac ?

Feb 28, 2021
2
0
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Hi,

I just to finish to setup my new config.
  • ASRock B460M-ITX/ac
  • 32 go RAM
  • i7 10700k
  • M2 SSD
  • Noctua NH-L9x65 CPU Cooler
  • 2 chassis FAN be quiet shadow wings 2 - PWM - 1100RPM
While I check in the BIOS I encounter I think an issue with strange fan behavior. Fan on CHA_FAN1 has high speed most of time ~1300 RPM. Beside, CPU_FAN1 run at ~700 and CHA_FAN2 at ~700 to ~900RPM.
Settings for CHA_FAN1 are:
  • control mode: PMW
  • setting: Standard Mode
  • temp source: mother-board
  • step up: level 0
  • step down: level 0
I have tried to set by percents (temps curve) and other settings but CHA_FAN1 seems do not respect any rules. Like I say It Is stuck at ~1300 RPM most of time while temperature is low.
I have flash BIOS 1.10 to 1.40 and on the next reboot RPM was good at ~700 RPM for a few minutes before increasing again for no reason.
Should I consider that the mother-board has an issue on CHA_FAN1 connector ? And how is it possible that my fan that is supposed to have a max speed to 1100RPM can speed up over this specification ?

My settings:
View: https://imgur.com/jhNR8R8

View: https://imgur.com/42jBtdL

View: https://imgur.com/zQbLSi6


Any help is welcome.
 
Last edited:

Lutfij

Titan
Moderator
If you read through guides on how to update the BIOS, you're always advised to gradually work your way to the latest version. In your instance, you should've gone with 1.10>1.20>1.40. Another thing is, you should've gone with a Z470/490 chipset for your motherboard to pair with that unlocked processor.

You might want to swap places with the fans/fan headers for the chassis fans and see if they behave the same way. I'd try and get a fan splitter off the header that responds to your inputs and leave the other header alone.
 
Feb 28, 2021
2
0
10
In your instance, you should've gone with 1.10>1.20>1.40.
Missed this.

Another thing is, you should've gone with a Z470/490 chipset for your motherboard to pair with that unlocked processor.
I do not intend to overclock my cpu for now.

I have tried to swap fans from CHA_FAN1 and CHA_FAN2 and I had same behavior as before (fan on CHA_FAN1 spins at 1200-1300 RPM). On the other and, HWMonitor reports higher temperatures than BIOS:
View: https://imgur.com/S5Gqp8O


I do not know what to think about these temperatures greater than 65 °C in idle state. Maybe some temperature sensors get wrong output and that why CHA_FAN1 spins higher than the 2 other fans.