Energy consumption vs % utilization?

David Lesher wb8foz at nrk.com
Wed Oct 27 00:12:46 UTC 2004


Speaking on Deep Background, the Press Secretary whispered:
> 
> 
> You should be able to pick up simple current / wattage meter from local 
> hardware store for $20 or so. That will tell you that on a modern 
> dual-CPU machine the power consumption at idle CPU is about 60% of peak. 
> The rest is consumed by drives, fans, RAM, etc. As wattage the 
> difference is 100-120W (50-60W per cpu)

Bogus data alert....

A ammeter will tell you amps. But in the world of switcher power
supplies, that does not beget watts. [Why? is an exercise for
the student. Start with "power factor" and "VARS" and worry about
asymetric loads...] 

If you want to talk watts, as you must to worry about HVAC,
or really watt-hours... acquire a power company type meter - in
glass with a whirlygig. Put it in a meter box with plugs. [See
your local eletrical wholesaler..]

(The rotating disk watthour meter is amazingly accurate under
almost any kind of load waveform. Only time-of-day metering has
spurred the utilities to replace them.)

Plug the machines into it; it into the wall. Note the numbers
and the time, and come back in 24Hours. 




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