Implementations
Intel's CPU throttling technology, SpeedStep, is used in its mobile CPU line.
AMD employs two different CPU throttling technologies. AMD's Cool'n'Quiet technology is used on its desktop and server processor lines. 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. AMD's PowerNow! 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. The 167-processor AsAP 2 chip is the first multi-core processor chip which enables individual processors to make fully unconstrained changes to their own clock frequencies.
According to the ACPI Specs, the C0 working state of a modern-day CPU can be divided into the so-called "P"-states (performance states) which allow clock rate reduction and "T"-states (throttling states) which will further throttle down a CPU (but not the actual clock rate) by inserting STPCLK (stop clock) signals and thus omitting duty cycles.
Read more about this topic: Dynamic Frequency Scaling