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Cool'n'Quiet (to German: "cool and quiet") is a power-saving mode and modern as such a feature AMD - processors since the family AMD K8 as the Athlon 64 or Sempron . This is an improved version of the PowerNow! , which is also being used for the first time in workstation computers and servers .

The clock rate of the main processor (CPU) is reduced to 800 MHz or 1  GHz during phases of lower load, depending on the model  . In addition, the core voltage and the clock multiplier are dynamically reduced in up to 32 steps during operation. The control is carried out directly by an ACPI -compatible operating system . For Windows 98SE, ME, 2000 and XP, GNU / Linux (from Kernel 2.2), Open / Free / Dragonfly / Net-BSD (older systems are not ACPI-capable) AMD provides a processor driver ( amdk8.sys ) for this purpose, which makes it possible to address the processor as an ACPI processor object. The Linux cpufreq driver is also capable of Cool'n'Quiet. Regardless of the operating system used, the computer's BIOS must also support this power-saving mode, which is not always the case with all versions, and the mode must be activated in the BIOS.

An example of how Cool'n'Quiet can be used and how it works is the AMD Athlon 64 3700+ with CG stepping: It clocks from 2400 MHz (1.550  volts , multiplier 12) to 1000 MHz (1.10 volts, multiplier 5) down. As a result, the power consumption drops significantly: from a maximum of 89  watts to a maximum of 22 watts, which primarily benefits the battery life of the mobile Athlon 64 processors .

Due to the lower power loss , temperature-controlled processor fans can reduce the speed or even switch it off completely, which can further reduce power consumption. The sinking background noise also enables more pleasant work.

AMD Sempron processors based on Socket 754 only support Cool'n'Quiet from a clock frequency of 1800 MHz (from 3000+), regardless of the processor core used. The same applies to the socket AM2 semprons introduced in May 2006 . There, however, the processor receives a rating of 3200+ at 1800 MHz, which is due to the dual-channel memory controller , in contrast to the Socket 754 .

With Optimized Power Management (OPM), AMD Opteron processors basically have the same technology, but for marketing reasons it is called differently, as is the case with the AMD Turion 64 and other notebook processors , where Cool'n'Quiet is still PowerNow! called.

In March 2005, the Cool'n'Quiet technology was awarded the Energy Star label by the American Environmental Protection Agency (EPA) . With this award, the EPA recognized AMD as a processor manufacturer whose products save costs and energy and protect the environment, as the performance efficiency in PCs is significantly improved.

Freezing the system

On some hardware configurations, Cool 'n' Quiet freezes the system, in these cases this function can be switched off in the BIOS / UEFI.

Processors with Cool'n'Quiet

See also