To test power consumption today we are using a calibrated energy meter. We loaded the system with Cinebench and 3DMark11 and measured results at idle and load.
The Sapphire EDGE HD4 Mini PC sips power at the socket, taking only 14.6 watts when idle. When under load this rises to around 24 watts. It would be fair to say that this is one of the most efficient little systems we have ever tested!