@Michael:

Reading the article, every test result my brain stretched and wondered what was wrong. Yet, asmcgregalready said, the only really valid number to compare the processors' efficiency is to calculate the energy which is needed to get the job done. And this, Michael, should be sone by calculating the integral of your W(t) curves... As you have discrete measurements with a fixed step size in time, dt, it's nothing more than a sum over all measurements, multiplied by dt.

dt * \sum_{i=0}^{N} W_i

If you know how many floating point operations this task needs, you can calculate the energy per floating point operation -- which is the same as the average number of Watts per Speed (measured in flop / sec).