AMD Cool'n'Quiet is a

CPU A central processing unit (CPU), also called a central processor, main processor or just processor, is the electronic circuitry that executes instructions comprising a computer program. The CPU performs basic arithmetic, logic, controlling, a ...

dynamic frequency scaling and power saving technology introduced by AMD with its Athlon XP processor line. It works by reducing the processor's clock rate and

voltage Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to ...

when the processor is idle. The aim of this technology is to reduce overall power consumption and lower heat generation, allowing for slower (thus quieter)

cooling fan A fan is a powered machine used to create a flow of air. A fan consists of a rotating arrangement of vanes or blades, generally made of wood, plastic, or metal, which act on the air. The rotating assembly of blades and hub is known as an '' ...

operation. The objectives of cooler and quieter result in the name Cool'n'Quiet. The technology is similar to Intel's

SpeedStep Enhanced SpeedStep is a series of dynamic frequency scaling technologies (codenamed Geyserville and including SpeedStep, SpeedStep II, and SpeedStep III) built into some Intel microprocessors that allow the clock speed of the processor to be dyna ...

and AMD's own

PowerNow! __NOTOC__ AMD PowerNow! is AMD's dynamic frequency scaling and power saving technology for laptop processors. The CPU's clock speed and VCore are automatically decreased when the computer is under low load or idle, to save battery power, red ...

, which were developed with the aim of increasing laptop battery life by reducing power consumption. Due to their different usage, ''Cool'n'Quiet'' refers to desktop and server chips, while ''PowerNow!'' is used for mobile chips; the technologies are similar but not identical. This technology was also introduced on "e-stepping"

Opteron Opteron is AMD's x86 former server and workstation processor line, and was the first processor which supported the AMD64 instruction set architecture (known generically as x86-64 or AMD64). It was released on April 22, 2003, with the ''Sledg ...

s, however it is called ''Optimized Power Management'', which is essentially a re-tooled Cool'n'Quiet scheme designed to work with registered memory. ''Cool'n'Quiet'' is fully supported in the

Linux kernel The Linux kernel is a free and open-source, monolithic, modular, multitasking, Unix-like operating system kernel. It was originally authored in 1991 by Linus Torvalds for his i386-based PC, and it was soon adopted as the kernel for the GNU ...

from version 2.6.18 onward (using the powernow-k8 driver) and FreeBSD from 6.0-CURRENT onward.

Implementation

In-order to take advantage of Cool'n'Quiet Technology in Microsoft's Operating Systems: * Cool'n'Quiet should be Enabled in system BIOS * In Windows XP and 2000: Operating Systems "Minimal Power Management" profile must be active in "Power Schemes". A PPM driver was also released by AMD that facilitates this. * In Windows Vista and 7: "Minimum processor state" found in "Processor Power Management" of "Advanced Power Settings" should be lower than "100%". Also In Windows Vista and 7 the "Power Saver" power profile allows much lower power state (frequency and voltage) than in the "High Performance" power state. Unlike Windows XP, Windows Vista only supports Cool'n'Quiet on motherboards that support

ACPI Advanced Configuration and Power Interface (ACPI) is an open standard that operating systems can use to discover and configure computer hardware components, to perform power management (e.g. putting unused hardware components to sleep), auto con ...

2.0 or later. With earlier versions of Windows, processor drivers along with Cool'n'Quiet software also need to be installed. The latest version is 1.3.2.0.

Third party utilities

In addition to the CPU drivers offered by AMD, several motherboard manufacturers have released software to give the end user more control over the ''Cool 'n' Quiet'' feature, as well as the other new features of AMD processors and chipsets. Using these applications, one can even control the CPU voltage explicitly.
PhenomMsrTweaker (SourceForge link)
# RMClock

Processors supporting Cool'n'Quiet

* Athlon XP *

Athlon 64 The Athlon 64 is a ninth-generation, AMD64-architecture microprocessor produced by Advanced Micro Devices (AMD), released on September 23, 2003. It is the third processor to bear the name ''Athlon'', and the immediate successor to the Athlon XP. T ...

and X2 – all models * Athlon 64 FX – FX-53 ( Socket 939 only) and higher * FX (Socket 942) * Athlon II – all models * Sempron – Socket 754: 3000+ and higher;

Socket AM2 The Socket AM2, renamed from Socket M2 (to prevent using the same name as Cyrix MII processors), is a CPU socket designed by AMD for desktop processors, including the performance, mainstream and value segments. It was released on May 23, 2006, as ...

: 3200+ and higher * Opteron – E-stepping and higher, branded as ''Optimized Power Management'' * Phenom – all versions support Cool'n'Quiet 2.0 * Phenom II – supports Cool'n'Quiet 3.0 * some of the

APUs Apus is a small constellation in the southern sky. It represents a bird-of-paradise, and its name means "without feet" in Greek because the bird-of-paradise was once wrongly believed to lack feet. First depicted on a celestial globe by Pet ...

* Ryzen – 3, 5, 7, and 9 all models support Cool ‘n’ Quiet *

EPYC Epyc is a brand of multi-core x86-64 microprocessors designed and sold by AMD, based on the company's Zen microarchitecture. Introduced in June 2017, they are specifically targeted for the server and embedded system markets. Epyc processors share ...

References

External links

AMD Cool'n'Quiet 2002

Phenommsrtweaker

Custom Cool'n'Quiet
{{Computer processor power management technologies Computer hardware tuning AMD technologies Clock signal 2002 introductions X86 architecture

Implementation

Third party utilities

Processors supporting Cool'n'Quiet

See also

References

External links