Power Management

Power Management is a feature of some electrical appliances, especially , computers, GPUs and computer peripherals such as monitors and printers, that turns off the power or switches the system to a low-power state when inactive. In computing this is known as PC power management and is built around a standard called ACPI. This supersedes APM. All recent (consumer) computers have ACPI support.

In the military, ""Power Management"" often refers to suites of equipment which permit soldiers and squads to share diverse energy sources, powering often incompatible equipment.

PC power management for computer systems is desired for many reasons, particularly:

Lower power consumption also means lower heat dissipation, which increases system stability, and less energy use, which saves money and reduces the impact on the environment.

The power management for microprocessors can be done over the whole processor, or in specific components, such as cache memory and main memory.

With dynamic voltage scaling and dynamic frequency scaling, the CPU core voltage, clock rate, or both, can be altered to decrease power consumption at the price of potentially lower performance. This is sometimes done in real time to optimize the power-performance tradeoff.

Examples:

Additionally, processors can selectively power off internal circuitry (power gating). For example:

Intel VRT technology split the chip into a 3.3V I/O section and a 2.9V core section. The lower core voltage reduces power consumption.

ARM's big.LITTLE architecture can migrate processes between faster "big" cores and more power efficient "LITTLE" cores.

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