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Date:      Fri, 10 Aug 2007 13:15:19 +0200
From:      =?utf-8?Q?Dag-Erling_Sm=C3=B8rgrav?= <des@des.no>
To:        Pietro Cerutti <gahr@gahr.ch>
Cc:        freebsd-hackers@freebsd.org
Subject:   Re: Core temperature
Message-ID:  <86r6mb7i9k.fsf@ds4.des.no>
In-Reply-To: <46BC4309.8000802@gahr.ch> (Pietro Cerutti's message of "Fri\, 10 Aug 2007 12\:50\:49 %2B0200")
References:  <86myx0pa9i.fsf@ds4.des.no> <46BC4309.8000802@gahr.ch>

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Pietro Cerutti <gahr@gahr.ch> writes:
> Could you please try to explain these results?
>
> % sysctl hw.coretemp.tjmax hw.coretemp.delta hw.acpi.thermal.tz0.temperat=
ure
> hw.coretemp.tjmax: 100
> hw.coretemp.delta: -38
> hw.acpi.thermal.tz0.temperature: 66.8C
>
> Shouldn't hw.coretemp.delta 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
hw.coretemp.delta 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
hw.coretemp.delta: -46

although I believe this is actually one of the CPUs that have an 85=C2=B0C
Tj(max), giving a core temperature of 39=C2=B0C and not 54=C2=B0C (the box =
has a
2.4 GHz C2D but spends most of its time barely ticking over at 200 MHz)

DES
--=20
Dag-Erling Sm=C3=B8rgrav - des@des.no



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