Definition - What does Power Management mean?
Power management is a computing device feature that allows users to control the amount of electrical power consumed by an underlying device, with minimal impact on performance. It enables the switching of devices in various power modes, each with different power usage characteristics related to device performance.
Techopedia explains Power Management
A native feature of most hardware devices, power management is managed by a computer's preinstalled firmware or installed host operating system (OS). Firmware or a host OS typically uses Advanced Configuration and Power Interface (ACPI) to access a computer's power features.
In Windows 7 and later operating systems, a device can operate by default between five different power modes: high performance, balanced, power saver, sleep and hibernate. A system's performance is optimal but consumes more energy in high performance mode, whereas power saver mode saves energy but provides less performance.
Additionally, power settings may be manually adjusted to configure computer brightness, end unnecessary backend device services or switch a computer to sleep mode, etc.