The HLT signal which is used by the normal idle-loop of the Linux kernel doesn't normaly bring any significant power-saving on processors of the Athlon/Duron family (hereafter referred to as Athlon processors). To get real power-saving on an Athlon processor, you have to put the processor in the STPGNT-Mode (Stop Grant Mode). In this mode, the processor is disconnected from the front-side bus (FSB), and can turn off parts of the CPU as well as reduce the clock to save power.
Some modern Motherboards/Chipsets also support a Function to make a STPGNT when a HLT signal is detected.
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Feedback is most essential for this document. New solutions for new chipsets are especially needed, as are comments, whether the provided solutions work or don't work. Also please report spelling errors if you find them, cause i am no native english speaker. Send your additions, comments, criticisms and questions to the following email address: <daniel@nofftz.net.NOSPAM>. You can email me in German or English!
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