Top node hotter thanothers?

Michael Stein mas at ucla.edu
Fri Jul 25 14:37:19 EDT 2003


> node case    cpu
> 01   +34°C   +43°C 
> 02   +35°C   +44°C 
> 03   +37°C   +48°C 
> 04   +42°C   +50°C 
> 05   +38°C   +48°C 
> 06   +37°C   +50°C 
> 07   +36°C   +45°C 
> 08   +38°C   +48°C 
> 09   +38°C   +48°C 
> 10   +38°C   +48°C 
> 11   +36°C   +44°C 
> 12   +38°C   +48°C 
> 13   +38°C   +48°C 
> 14   +40°C   +49°C 
> 15   +38°C   +46°C 
> 16   +36°C   +46°C 
> 17   +39°C   +51°C 
> 18   +39°C   +48°C 
> 19   +39°C   +49°C 
> 20   +44°C   +54°C

It's not clear to me that there is an actual difference going toward
the top.  04 is +42?

Assuming the input air temperature is reasonably uniform over the
machines, I'd guess that you're seeing a combination of different
sensor calibration and different heat dissipation (or different fan
capabilities).  Ignoring sensor error, the hotter machines must have
either higher power input or less air flow (assuming similar input air
temperature).

There is a tolerance on CPU (and other chips) heat/power usage -- some are
bound to run hotter than others.

Or check what's running on each machine.  This can make a huge difference.
I've seen output air on one machine go from 81 F to 99 F (27 C to 37 C)
from unloaded to full load (dual Xeon, 2.4 Ghz, multiple burnP6+burnMMX).
This was with 72 F input air (22 C).
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