CPU fan speed error

hasuuu

Commendable
Mar 29, 2016
8
0
1,510
I realize that this question has been asked a million times, but bear with me.

Usually but not always (approx. 7 out of every 8 boots) I get a "CPU fan speed error detected" on boot. My motherboard is an Asus Z170-A and my cooler is a Thermalright TRUE Spirit 140 BW Rev A.

I've triple-checked that the CPU fan is plugged into the CPU_FAN connector correctly, and definitely not plugged into the CPU_OPT connector. The UEFI reports that the fan is running at ~320rpm. The minimum fan speed in the UEFI (below which an error should be reported) is 200rpm. And the only option lower than 200rpm is 0, which I would prefer not to set.

The CPU temp is usually around 27C.

Here's the weird part: Most of the time when I boot up, the CPU fan slightly twitches, then doesn't move for 4 seconds, and then starts spinning. From what I understand this is normal CPU fan behavior. But every once in a while the CPU fan starts spinning immediately, without any delay, and these times are exactly the times when I don't get the "CPU fan speed error detected" message.

The inconsistent fan behavior, coupled with the fan speed error messages, is leaving me baffled. And I haven't been able to find any similar problem descriptions elsewhere online.

Any ideas? Thanks!
 

Colif

Win 11 Master
Moderator
are you running AI suite? Fan controlled through software or bios? just curious... probably not even related.

I used to use AI suite to control fans until some really cold nights it would actually turn my CPU fan off altogether. That is scary as hell, the case fans would go mad... and the main reason I don't run AI suite anymore. I let the bios do it... my case is just different and I wanted to make sure it never turned the intake fans off
 

hasuuu

Commendable
Mar 29, 2016
8
0
1,510


Not running AI suite. I'm controlling the fans through the UEFI, and even under the coolest conditions the CPU fan should be (and is) running at 300rpm.
 

hasuuu

Commendable
Mar 29, 2016
8
0
1,510
I set the "CPU fan speed low limit" to "Ignore" in the UEFI and I'm still getting a CPU fan speed error on boot :(

My UEFI version is the latest. Any ideas?