Dynamic voltage and frequency scaling (DVFS) is the adjustment of power and speed settings on a computing device’s various processors, controller chips and peripheral devices to optimize resource allotment for tasks and maximize power saving when those resources are not needed.
DVFS allows devices to perform needed tasks with the minimum amount of required power. The technology is used in almost all modern computer hardware to maximize power savings, battery life and longevity of devices while still maintaining ready compute performance availability.
An unused smartphone, for example, should revert to a low-power mode, barring interference from applications and spyware. Multimedia requires more power, so the device reaches a higher power state and creates more heat during heavier processing such as video and gaming. Were it not for DVFS, many devices that are passively cooled would require active cooling. However, the noise, bulk and power consumption required by active cooling makes it impractical for smaller devices. DVFS helps maintain operable parameters with increased mobility.
DVFS is not reserved for mobile technology alone. Desktops, servers and virtual environments also benefit from the power savings of DVFS. In VMware vSphere, DVFS allows host CPUs to dynamically change power states when resource demands are low to reduce a host's energy consumption. CPU frequency and voltages are lowered and raised based on demand from virtual machines (VMs).
While more important in environments with large numbers of computers, like offices, server farms and data centers, individual users are also paying more attention to power consumption. DVFS can also scale upwards to increase performance. Both AMD and Intel feature similar technology, often referred to as “turbo mode” for short runs of speeds beyond what the device could maintain indefinitely, at least with default cooling.