Program Execution Speed
The speed at which a digital circuit can switch states - that is, to go from "low" (VSS) to "high" (VDD) or vice versa - is proportional to the voltage differential in that circuit. Reducing the voltage means that circuits switch slower, reducing the maximum frequency at which that circuit can run. This, in turn, reduces the rate at which program instructions that can be issued, which may increase run time for program segments which are sufficiently CPU-bound.
This again highlights why dynamic voltage scaling is generally done in conjunction with dynamic frequency scaling, at least for CPUs. There are complex tradeoffs to consider, which depend on the particular system, the load presented to it, and power management goals. When quick responses are needed, clocks and voltages might be raised together. Otherwise, they may both be kept low to maximize battery life.
Read more about this topic: Dynamic Voltage Scaling
Famous quotes containing the words program, execution and/or speed:
“[T]he minister preached a sermon on Jonah and the whale, at the end of which an old chief arose and declared, “We have heard several of the white people talk and lie; we know they will lie, but this is the biggest lie we ever heard.””
—Administration in the State of Miss, U.S. public relief program (1935-1943)
“It is clear that in a monarchy, where he who commands the exceution of the laws generally thinks himself above them, there is less need of virtue than in a popular government, where the person entrusted with the execution of the laws is sensible of his being subject to their direction.”
—Charles Louis de Secondat Montesquieu (1689–1755)
“There was such speed in her little body,
And such lightness in her footfall,
It is no wonder her brown study
Astonishes us all.”
—John Crowe Ransom (1888–1974)