Dell Optiplex 7090 SFF fan noise

Hi,

I just got a new Dell Optiplex 7090 SFF (small form factor). Unfortunately, the fan is constantly running, even when the machine is idle. When the machine is under stress for some time, the fan gets only slightly louder, so the minimum fan speed seems way too high. The CPU temperatures also look fine: 27C - 34C CPU temperature when idle in the on-board diagnostics tool.

Looking at the in-built diagnostics, the system info says 890 RPM for the current CPU fan speed (with 888 RPM for low and 1223 RPM for high). That doesn't sound too high, but it's still noticeable.

Did I get a bad device or did Dell really cheap out on a quality fan and useful fan control to ensure that the machine is silent when it's idle?

I already updated to the latest BIOS version 1.2.1, which didn't change anything. I found a single option in the BIOS related to fan control ("Override Fan Control"), but that just makes the fan run at full speed all the time, which sounds a bit like an airplane taking off, and is the opposite from what I want.

My machine runs Linux (RHEL 8 compatible), and I unfortunately could not find a way to overwrite the fan behavior through software.

Any help is appreciated.

Thanks!