Power consumption -- real vs actual

John LLOYD jal at mdacorporation.com
Mon Apr 5 14:20:22 CDT 2010

> > FYI, commands were
> >  CPU heater:  dd if=/dev/zero of=/dev/null  &    8 to 16 times
> That's not a terribly good CPU-intensive load.  Try something like
> this a few times in parallel
> pi=$(echo "scale=100000; 4*a(1)" | bc -l)  &
> I can feel the space under my desk heating up after just a few seconds
> of this...
> Thanks,
> Matt

Switching to Matt's suggested heater, and revising tar to pipe to a dd (apparantly tar can tell when you are throwing away it's output...), I get 427 watts.   Or, 413 watts, after a few minutes.  Or 420, after a few more.  So this is a little more like what would be expected from the calc website (252).

cpu heater:  pi=$(echo "scale=100000; 4*a(1)" | bc -l)  &   ( 8 times )
disk heater: tar cf - /amsdata | dd of=/dev/null

The question remains what is it actually measuring?


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