Cool'n'Quiet is a CPU speed throttling and power saving technology introduced by AMD with their Athlon 64 processor line. It works by reducing the processor's clock rate and voltage 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 exactly equivalent. 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 Linux from 2.6.18 and FreeBSD from 6.0-CURRENT onward (using the powernow-k8 driver).[1][2] Unlike Windows XP, Windows Vista only supports Cool'n'Quiet on motherboards that support ACPI 2.0 or later. In earlier versions of Windows processor drivers / Cool'n'Quiet software needs to be installed.[3]
Processors supporting Cool'n'Quiet
- Athlon 64 and X2 - all models
- Athlon 64 FX - FX-53 (Socket 939 only) and higher
- Sempron - 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 - supports Cool'n'Quiet 3.0
References
- ^ "Linux kernel CPUfreq subsystem - hardware". The Linux Kernel Archives. http://www.kernel.org/pub/linux/utils/kernel/cpufreq/hardware.html. Retrieved on 2007-08-18.
- ^ "What's New in FreeBSD 7.0" (HTML). O'Reilly Media, Inc.. 2008-02-26. http://www.onlamp.com/pub/a/bsd/2008/02/26/whats-new-in-freebsd-70.html?page=2. Retrieved on 2008-05-19.
- ^ "Cool'n'Quiet Technology Installation Guide for AMD Athlon 64 Processor Based Systems" (PDF). Advanced Micro Devices, Inc.. 2004-06. http://www.amd.com/us-en/assets/content_type/DownloadableAssets/Cool_N_Quiet_Installation_Guide3.pdf. Retrieved on 2007-08-18.
External links
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