Instead of pasting the wall of text, there is a very good writeup about it in the HWiNFO forum.
But the TL;DR of it is that AMD's spec allows the motherboard manufacturers to basically lie in their reporting to the CPU as to how much power it's actually drawing which allows for higher clocks at the expense of power consumption and heat production, and is no doubt a cause of a lot of these "*** IS WITH THESE TEMPS WITH THE STOCK COOLER AND STOCK SETTINGS OMG!!!" types of threads we have seen on here.
Now, AMD knows about this deception, but they really can't do anything about it. The article states they "actively put pressure" on them to stop, but they don't really have the power to do it.
Now, the way you use it is to download it, which is available only as a portable version right now, which isn't a big deal since it won't mess with your current install, and let it run while you run a processor intensive task, they recommend Cinebench R20 which really is the most processor intensive yet realistic load you can put on it. Now, I'm overclocking and undervolting which explains the greater than 100% figures, but when you start seeing figures of 90%, 80%, or even 50%, that's where it's reporting up to half of the actual power consumption
And again, to quote:
Until now, you just couldn't actually see it.