AMD Cool'n'Quiet is a
CPU 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
Clock rate or clock speed in computing typically refers to the frequency at which the clock generator of a processor can generate pulses used to synchronize the operations of its components. It is used as an indicator of the processor's s ...
and
voltage
Voltage, also known as (electrical) potential difference, electric pressure, or electric tension, is the difference in electric potential between two points. In a Electrostatics, static electric field, it corresponds to the Work (electrical), ...
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 operation. The objectives of cooler and quieter result in the name Cool'n'Quiet. The technology is similar to
Intel's SpeedStep and AMD's own
PowerNow!, 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"
Opterons, 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 software, free and open source Unix-like kernel (operating system), kernel that is used in many computer systems worldwide. The kernel was created by Linus Torvalds in 1991 and was soon adopted as the k ...
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 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. ...
and
X2 – all models
* Athlon 64 FX – FX-53 (
Socket 939 only) and higher
*
FX (Socket 942)
*
Athlon II – all models
*
Sempron
Sempron has been the marketing name used by AMD for several different budget desktop CPUs, using several different technologies and CPU socket formats. The Sempron replaced the AMD Duron processor and competed against Intel's Celeron#Celeron D (Pr ...
–
Socket 754: 3000+ and higher;
Socket AM2: 3200+ and higher
* Opteron – E-stepping and higher, branded as ''Optimized Power Management''
*
Phenom – all versions support Cool'n'Quiet 2.0
*
Phenom II
Phenom II is a family of AMD's multi-core 45 nm central processing unit, processors using the AMD K10 microarchitecture, succeeding the original AMD Phenom, Phenom. Advanced Micro Devices released the Socket AM2+ version of Phenom II in Dece ...
– supports Cool'n'Quiet 3.0
* some of the
APUs
*
Ryzen – 3, 5, 7, and 9 all models support Cool ‘n’ Quiet
*
EPYC
See also
*
Dynamic frequency scaling
Power Saving Technologies:
*
AMD PowerNow! (laptop CPUs)
*
AMD PowerTune/
AMD PowerPlay (graphics)
*
AMD PowerXpress (multi-graphics)
*
Intel SpeedStep (CPUs)
Performance Boosting Technologies:
*
AMD Turbo Core (CPUs)
*
Intel Turbo Boost (CPUs)
References
External links
AMD Cool'n'Quiet 2002PhenommsrtweakerCustom Cool'n'Quiet
{{Computer processor power management technologies
Computer hardware tuning
AMD technologies
Clock signal
2002 introductions
X86 architecture