Dynamic frequency scaling (also known as CPU throttling) is a power management technique in computer architecture whereby the frequency of a microprocessor can be automatically adjusted "on the fly" depending on the actual needs, to conserve power and reduce the amount of heat generated by the chip.
Dynamic frequency scaling helps preserve battery on mobile devices and decrease cooling cost and noise on quiet computing settings, or can be useful as a security measure for overheated systems (e.g. after poor overclocking).
Dynamic frequency scaling almost always appear in conjunction with dynamic voltage scaling, since higher frequencies require higher supply voltages for the digital circuit to yield correct results.
[5] Leakage current has become more and more important as transistor sizes have become smaller and threshold voltage levels are reduced.
This abstraction provides some leeway for the processor to adjust its workings in ways other than just the frequency.
Dynamic frequency scaling by itself is rarely worthwhile as a way to conserve switching power.
The aim of Cool'n'Quiet is not to save battery life, as it is not used in AMD's mobile processor line, but instead with the purpose of producing less heat, which in turn allows the system fan to spin down to slower speeds, resulting in cooler and quieter operation, hence the name of the technology.
CPU throttling technology is used in its mobile processor line, though some supporting CPUs like the AMD K6-2+ can be found in desktops as well.
The 36-processor AsAP 1 chip is among the first multi-core processor chips to support completely unconstrained clock operation (requiring only that frequencies are below the maximum allowed) including arbitrary changes in frequency, starts, and stops.