Microserver Gen8 ILO constantly shows CPU temperature 40 °C

[ArnisR]

Just subj. Whatever CPU do, ILO reports 40 °C

Microserver Gen8 1610T, RAID enabled

[Oscar A. Perez]

The CPU temperature sensor isn't very accurate below 40 Celcuis so, in order to prevent customers from asking "why my Proc is showing weird values?",  iLO is hardcoded to show a minimum temp of 40 C.

If you stress your processor using a tool like prime95, you will see the CPU temperature going up.

[ArnisR]

Thanks for explanation.

However a little bit strange.
I tortured Microserver with Prime95 more than hour. Every component (except inlet air) goes over 40°, but not CPU. Fan goes up to 50 %.

[Oscar A. Perez]

I just tortured my Microserver Gen8 using Prime95 and got the CPU temperature to increase to 42 ºC

I'm using iLO4 v2.10, by the way.

[FCM1]

Hi Oscar,

Could you please share your config, what CPU are you using.

Could you also confirm the temp readout in iLO is 100% correct via read-outs from the OS?

Thank you very much,

[AM7]

Hello,

I am facing the same issue and I addressed it to HPE Support and I am not ok with the provided resolution. I tested the temperatures in idle / full load with a thermometer and also with the LM-sensors tool under Debian Linux and there was clearly an increase of over 10degC but ILO showed the same steady value of 40degC.

There were people on the forums that installed the 80W TDP Xeon CPUs using the original heat sink and the temperature was 40degC which is not possible. I replicated the behavior on more then 4 Microservers but HPE Support doesn't want to understand the issue and wants to close the ticket with an unacceptable resolution.

I strongly believe that there is a firmware issue affecting these Proliant Microserver Gen8 and ILO doesn't report the correct CPU temperature risking overheating and CPU damage.

Later Edit: As a refference, you could check CASE:5315991863

Thanks,

Alexandru

[9yn16ijqi]

Has this been resolved or was there any update after the firmware updates intervened between 2016 and now (2025)?

I have measured the temperatures, especially the CPU, and till find a 40 degrees on the CPU, versus 52 from the OS and 45-48 on the surface of the heatsink. From this it seems that the OS is correct and iLO is wrong. I notice that the OS considers 85 as a threshold temperature, while iLO suggests 70 degrees.

It is quite strange that such an objective quantity is read so differnt from the same hardware.

Is there any documentation of the CPU temperature sensor of this server? I suspect the raw reading is parsed differently from the OS library and from iLO, possibly with a bug in iLO.

[Sunitha_Mod]

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