true power consumption (was: disadvantages of linux cluster)

alvin at alvin at
Fri Nov 8 14:45:49 PST 2002

hi ya

more cpu power dissipation and other specs

c ya

On Fri, 8 Nov 2002, Dave Lane wrote:


> I haven't been doing the same thing here over the last two days and you 
> have to be very careful when interpreting these measurements. Most meters 
> assume that the waveform is sinusoidal and use this fact to guess what 
> "RMS" current reading to display on the meter. Switching power supplies 
> have nothing like a sinusoidal current waveform.
> I have been measuring the supply current (120V) for an Athlon XP1700 PC 
> running Linux (MSI KT266A MB, 20G drive, CD, floppy, KB, Mach64 video). For 
> cpu loading I'm using the setiathome cmdline version). The measurement 
> technique is inline (I made a custom cable to do this) with both normal 
> (Fluke 73UIII) and true-rms (Fluke 79III) multimeters.
>                  Unloaded (A)    Loaded (A)      Unloaded (W)    Loaded 
> (W)
> Normal          0.65A           0.74A           78W             88.8W
> True RMS        1.13A           1.3A            135W            156W

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