Core temperature

Dag-Erling Smørgrav des at
Fri Aug 10 04:15:23 PDT 2007

Pietro Cerutti <gahr at> writes:
> Could you please try to explain these results?
> % sysctl hw.coretemp.tjmax hw.acpi.thermal.tz0.temperature
> hw.coretemp.tjmax: 100
> -38
> hw.acpi.thermal.tz0.temperature: 66.8C
> Shouldn't be (hw.coretemp.tjmax -
> hw.acpi.thermal.tz0.temperature)?

The value reported by hw.acpi.thermal.tz0.temperature most likely comes
from a temperature sensor mounted somewhere on the motherboard, while reports the temperature inside the CPU itself.  In my
experience, Core-based CPUs run very cool under light load, so the
result does not surprise me.

here's what coretemp reports on my file server:

hw.coretemp.tjmax: 100 -46

although I believe this is actually one of the CPUs that have an 85°C
Tj(max), giving a core temperature of 39°C and not 54°C (the box has a
2.4 GHz C2D but spends most of its time barely ticking over at 200 MHz)

Dag-Erling Smørgrav - des at

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