Yeah I know that specs generally mean nothing or at least not much but still I have to wonder how broad the UL rules are for listing these specs. I know for a fact that Denon and Harman Kardon list the maximum current draw at the rated output for their receivers. The 7200 uses a max of 1050 watts and the Denon 5800 uses 12amps , 120v x 12 amps is 1440 watts. On the other hand Yamaha does not say how they come up with their wattage rating , they simply have on the RX-Z1 "Power consumption 650watts" Now what do we know about the Z1 and 5800? Hard evidence by Sound and Vision is this: The Denon 5800 is rated at 170x7 and S&V measured it to put out 138x5/118x7 with all channels driven with .05% distortion. The Yamaha RX-Z1 is rated at 130x6 and S&V measured it at 117x5/109x6 with all channels driven and a very low .015% distortion. How much power does the Denon put out at .015% distortion? I'd wager that these two amps are fairly similar if you were shooting to keep the distortion figures the same. Yet the Denon uses 1440 watts and the Yamaha uses 650watts , so either they have a very broad range for rating their receivers or these two designs are very different. Perhaps Yamaha's amp is indeed nearly 3x more efficient then the Denon? I know these are just ratings and should be disregarded for the most part but I would like to know a little bit on how these companies come up with these numbers. Anyone care to comment?