Energy Star
Rating labels have been created by various organizations and working groups to evaluate the energy use of personalcomputers: Energy Star is one of them, as is the Blue Angel, the EU Eco-Label or the TCO guidelines forpersonal computers.
The Energy Star guidelines were developed by the US Environmental Protection Agency( EPA). The corresponding Energy Star label is internationally recognized. The guidelines have been amended several times and the current version classifies the power consumption of desktops, notebooks and peripherals, both in standby mode and in operation, and prescribes maximum values for standby operation. There are different Energy Star classes for desktops and notebooks, designated by the letters "A", "B" and "C", which differ in terms of processor technology.
According to these, desktops with multi-core processors may consume 65 W in idle mode; if they are equipped with a graphics card with at least 1 gigabyte( GB), the energy consumption can rise to 95 W. The Energy Star guidelines also deal with the efficiency of power supplies. According to the version from mid-2007, the directive stipulates an efficiency of at least 80%, at a load of 20% of the maximum permissible load.