Case fans revving up to max speed every time the hard drives churn a bit

[neoform]

Hello,

I've noticed my three 140mm case fans (located in front aimed at the hard drives and motherboard) seemingly revs up to max speed (for a few seconds, then drop right back down) any time the hard drives do even a bit of churning. Looking at the system temps, they're completely stable, disks are not even warm to the touch...

Any idea why the fans seem to constantly spin up and down over and over?

The machine:

* AMD Ryzen Threadripper 3970X 32-Core 3.7 GHz
* AsRock Rack TRX40D8-2N2T
* 5x Seagate Exos 16TB
* 8x Micron DDR4-3200 PC4-25600 16GB ECC UDIMM 1Rx8 - MTA9ASF2G72AZ-3G2B1
* Samsung EVO 970 500GB (boot disk)
* Seasonic SSR-850PX 850w Platinum
* Noctua NH-U14S TR4-SP3
* 4x Noctua NF-A14 iPPC-3000 PWM (4-pin)

 

[neoform]

Totally forgot,

Version:
TrueNAS-12.0-U5.1

 

[QonoS]

This is not controlled by TrueNAS, it is a BIOS thing. Just go to BIOS and do "FANTUNING" or however it is called. ;)

For the sake of completeness:
Link to AsRock Rack TRX40D8-2N2T Mainboard BIOS: https://download.asrock.com/Manual/TRX40D8-2N2T.pdf
As usually over the last years... mainboard producer do not care anymore to explain all BIOS options in manual.
But I am pretty sure you can configure how quickly FANs spin up/down when CPU/MB/whatever Temp goes up/down.

 

[neoform]

I went in to the bios and changed the case fans to be manual, I couldn't figure out a better way to prevent the fans from going berserk. Thanks.