Coretemp seems to be off quite a bit

[Frank Shute]

On Mon, Oct 06, 2008 at 09:39:40AM -0500, Kirk Strauser wrote:
>
> I have a Gigabyte motherboard with an Intel ICH-9 chipset, and a  
> 3.0GHz Core 2 Duo (E8400).  The coretemp sysctls seem to always show  
> 50C as the baseline temperature:
> 
> $ sysctl dev.cpu | grep temp
> dev.cpu.0.temperature: 50
> dev.cpu.1.temperature: 50
> 
> This is with a big PSU fan, a good CPU fan, a clean heatsink, and two  
> case fans aimed the right direction (front fan pulling cool air in,  
> rear fan pushing warm air out).  If I reboot and go into the BIOS, I  
> get numbers around 42-43C.  I know it's kind of hard to compare  
> directly, but the coretemp numbers are from a totally idle system with  
> powerd scaling it back to 373MHz, so it should be as cool as when  
> sitting idle in the BIOS screens.  When I work the system hard, like  
> running "make -j4 buildworld", I see temperatures up around 63-64C,  
> and I'm almost positive that's not right.
> 
> Any ideas why coretemp and the BIOS would show such different numbers?

To add some numbers, I've got an E6550 on a Gigabyte GA-P35-DS3L
(ICH9) and I get:

$ sysctl dev.cpu | grep temp
dev.cpu.0.temperature: 24
dev.cpu.1.temperature: 28

Ambient room temp: 23°C

That's running powerd and the machine idle, standard heatsink/fan
combo, 1x12cm case fan.

Your's might run hotter (higher clock speed? Mine: 2.33GHz) but I
wouldn't expect it to run *so* much hotter.

I'd expect your numbers to be right if all the ACPI stuff is working.
To confirm this, check in Windows, if you can:

http://www.techpowerup.com/realtemp/

Tom's hardware has some stuff about Intel temps:

http://www.tomshardware.co.uk/forum/221745-11-core-quad-temperature-guide

If that is high too and is outside the proper temperature envelope for
your CPU, that leaves a possibility that your heatsink/fan might not
be seated properly.

What we could do with is some numbers from somebody running a similar
CPU.

Regards,

-- 

 Frank 


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