Quote:
Originally posted by Les
Completed sums using my prefered method.
Ugh or Significant ?
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Interesting.
MOSFET's (the basic transistor building block of CPU's) leak. This current leakage is a major contributor to 'idle' power consumption in modern CPU's. The leakage goes up nonlinearly as temperature increases. It may be that the 'step' seen in the "C/W" curve is a step in power consumption due to leakage current dropping dramatically near -4C.
I've been somewhat expecting to find that such a step occurred. (Although this is a more dramatic transition than I would have guessed. And, at a dissapointingly low temperature.) Most likely this step is attributable to something other than a drop in leakage current, but if it is leakage current changing, it should be possible to detect it, by looking for discontinuities in 'idle' vs 'load' measurements at around 4C.
Because leakage current is also affected by voltage, the way to test for this would be by varying the CPU frequency only. I don't want to design an experiment right now, but if you are interested in trying it pH, let me know. Of course a Grothammeter would be awfully handy.