IBM's Technology Highlights for the Power Architecture wrote a very interesting article on the IBM PowerPC 970FX's power management that said several things that are relevant to this forum.
The article is: IBM PowerPC 970FX power envelope and power management
Figure 2 shows a nice "shmoo" plot of the part showing volage and frequency as well as power. A "shmoo" plot is a plot of frequency versus operating voltage for a CPU showing where the limits are. It's a very common debugging tool in CPU debugging. IBM has taken this type of chart and changed it by including power. It's interesting to see the effect increasing the voltage from 0.8V to 1.3V has on frequency which goes from 1.2GHz to 2.5GHz. And it's interesting to see the power go up from about 20W to 100W over that range.
There's also an interesting bit that mentions that increasing the voltage from 1.2V to 1.3V decreases the statistical operational lifetime of the part in half.
Overclockers.com has an article (which is here) on this as well. I disagree with some of what they wrote - or at least the way that they wrote it - but it's still an interesting read.
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