CPU Electrical Consumption

CPUs (Central processing units) in their various incarnations consume some amount of electric power. This power is dissipated both by the action of the switching devices contained in the CPU (such as transistors or vacuum tubes) as well as energy lost in the form of heat due to the resistivity of the electrical circuits. This is a major consideration in the design of CPUs and the computers they are used in.

Some implementations of CPUs use very little power. For example, the CPUs in mobile phones and pacemakers often use just a few microwatts. On the other hand, CPUs in general purpose microcomputers dissipate significantly more power because of their higher complexity and speed. These microelectronic CPUs may consume power in the order of several watts. Historically, early CPUs implemented with vacuum tubes consumed power in the order of many kilowatts (103 watts).

The complete, up-to-date and editable article about CPU Electrical Consumption can be found at Wikipedia: CPU Electrical Consumption
http://en.wikipedia.org/wiki/CPU_electrical_consumption