For example, notebook processors usually consume less power than their desktop counterparts, at the expense of computer performance.
[1] The earliest attempts to reduce the amount of power required by an electronic device were related to the development of the wristwatch.
They are very small and provide tiny amounts of power continuously for very long periods (several years or more).
[5] The density and speed of integrated-circuit computing elements has increased exponentially for several decades, following a trend described by Moore's Law.
While it is generally accepted that this exponential improvement trend will end, it is unclear exactly how dense and fast integrated circuits will get by the time this point is reached.
Working devices have been demonstrated which were fabricated with a MOSFET transistor channel length of 6.3 nanometres using conventional semiconductor materials, and devices have been built that use carbon nanotubes as MOSFET gates, giving a channel length of approximately one nanometre.
[6] This increase in consumption comes even though the energy consumed by a single CMOS logic gate in order to change its state has fallen exponentially in accordance with Moore's law, by virtue of shrinkage.
As the capacitive loads are charged and discharged through resistive devices, an amount of energy comparable to that stored in the capacitor is dissipated as heat: The effect of heat dissipation on state change is to limit the amount of computation that may be performed within a given power budget.
For some embedded systems that only function for short periods at a time, this can dramatically reduce power consumption.
The second approach is to attempt to provide charge to the capacitive loads through paths that are not primarily resistive.
As a practical rule of thumb, this means the change rate of a signal must be slower than that dictated by the RC time constant of the circuit being driven.
For clocked-logic circuits, the clock gating technique is used, to avoid changing the state of functional blocks that are not required for a given operation.
As a more extreme alternative, the asynchronous logic approach implements circuits in such a way that a specific externally supplied clock is not required.
While both of these techniques are used to different extents in integrated circuit design, the limit of practical applicability for each appears to have been reached.
[citation needed] There are a variety of techniques for reducing the amount of battery power required for a desired wireless communication goodput.
To reduce weight and cost, many laptop computers choose to use a much lighter, lower-cost cooling system designed around a much lower Thermal Design Power, that is somewhat above expected maximum frequency, typical workload, and typical environment.