[Beowulf] Benchmark between Dell Poweredge 1950 And 1435
Richard Walsh
rbw at ahpcrc.org
Fri Mar 9 12:59:41 PST 2007
Robert G. Brown wrote:
> Both good points. And those of us who have been around a while recall
> the "thermal throttle" that Intel in particular had installed on their
> CPUs for a while. You'd buy what was it a 1.6 GHz CPU at great expense,
> then run it flat out and as it got hot, it would suddenly underclock to
> 800 MHz?
This is a useful warning and resonates with a recent experience I have
had evaluating new hardware for acceptance and discovering the active
clock to be different from the nominal and /proc/cpuinfo reported clock.
We always do several things to verify clock one of which is to run
lmbench's mhz. This has always produced reliable numbers for me, but in
this recent case it consistently reported a 5% deficit even as the
/proc/cpuinfo
reported the nominal value. After some investigating by the vendor they
showed that on an upgraded BIOS the two are brought into alignment.
Without this test, who knows how long we might have been running
under-clocked.
As Robert often says never ASS-u-ME ...
rbw
Richard B. Walsh
Project Manager
Network Computing Services, Inc.
Army High Performance Computing Research Center (AHPCRC)
rbw at ahpcrc.org | 612.337.3467
>
> "The world is given to me only once, not one existing and one
> perceived. The subject and object are but one."
>
> Erwin Schroedinger
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