High PCH Temperature

[SeanZ89]

I bought a new Z2 Mini G4 recenntly which is currently running Ubuntu 18.10 and I realize the PCH temperature is rather high (around 80 C- 90 C) even after I have updated to the latest BIOS (Version: Q50 Ver. 01.01.08, Firwmware Revision 7.180).

When the load is low/close to idle, the CPU temperature is around 45 C, GPU temperature around 50 C but the PCH Temperature is around 90 C. Despite the PCH temperature is at 90C, the fan seems to be running at low speed.

pch_cannonlake-virtual-0
Adapter: Virtual device
temp1: +91.0°C

acpitz-virtual-0
Adapter: Virtual device
temp1: +30.0°C

iwlwifi-virtual-0
Adapter: Virtual device
temp1: N/A

coretemp-isa-0000
Adapter: ISA adapter
Package id 0: +44.0°C (high = +80.0°C, crit = +100.0°C)
Core 0: +42.0°C (high = +80.0°C, crit = +100.0°C)
Core 1: +43.0°C (high = +80.0°C, crit = +100.0°C)
Core 2: +42.0°C (high = +80.0°C, crit = +100.0°C)
Core 3: +44.0°C (high = +80.0°C, crit = +100.0°C)
Core 4: +44.0°C (high = +80.0°C, crit = +100.0°C)
Core 5: +42.0°C (high = +80.0°C, crit = +100.0°C)

The motherboard used is HP 8458 but I didn't manage to find any product specification online. The motherboard seems to be based on Intel's C246 Chipset? Considering the tightly packed components in the chassis, the temperature could be running higher than other normal desktops but is the PCH temperature around 90C in the normal operating range when idle/low usage?

However, when I stress load the CPU to 100%, the CPU temperature increases to the range of 85C - 90C and with the fan speen ramped up, the PCH temperature droped to 70C - 80C. It appears to me that the fan controller doen't take into account of the PCH temperature?

Appreciate if someone could help clarify if this is an expected behavior for the Z2 Mini G4. Thanks!

[DGroves]

workstation questions should be posted in the workstation forum where they stand a better chanch of getting a reply

https://h30434.www3.hp.com/t5/Business-PCs-Workstations-and-Point-of-Sale-Systems/bd-p/Business-PC-W...

the temps you are seeing is within the normal range of the Platform Controller Hub

this document while not for your exact chipset is within the same PCH family as your chipset and is still valid

https://www.intel.com/content/dam/www/public/us/en/documents/design-guides/9-series-chipset-pch-ther...

[SeanZ89]

Thanks for the reply, hopefully the moderator could help to move the thread to the workstation forum.

Looking at the specification sheet, Tj Max is 108C where the Hot Trip Point (throttling) begins? I would think (please correct me if I am wrong) that 90 C++ temp is quite close to the Tj Max and might impact the lifespan of the chipset, hence the fan speed should have increase? 

Not sure if there are any Auxilary Trip Point configurable in the BIOS that would trigger higher fan speed, but the CPU fan doesn't appear to be PWM controllable ("/usr/sbin/pwmconfig: There are no pwm-capable sensor modules installed").

[DGroves · Accepted solution]

the PCH does not throttle, and as i previously stated is rated for the temps you are seeing (and higher)  you are confusing the pch temp ratings (and your other asumptions)  with the CPU specs

the cpu fan is a 4 pin PWM type, and is controlled seperately from the case PWM fans

the CPU fan is under direct control of the cpu onboard temp sensor and this reading is sent to several points one of which allows you to read the current value/temp via software

or through the bios and another point (if enabled by the board maker) allows you to manually override the current cpu fan setting

in general, you should not change the auto settings on a system related to tempture unless you know exactly what you are changing and fully understand the ramifications of doing so

i recomend you read up on cpu throttling in general and also for your specific cpu you have