Cool'n'Quiet is the new developed technology of AMD PowerNow!, embedded in the AMD Athlon™64 processor. Under the normal circumstance, it can be enabled as long as the mainboard and BIOS support it. However, due to there are still some engineering sample processors sold in the market, we recommend buyer to check the model number first before buying it. Normally, as long as there is a "AO" or "AP" at the end of the model number, this CPU supports Cool'n'Quiet.Cool'n'Quiet appears to be a modified version of AMD's PowerNow! technology that throttles the Athlon 64 3200+'s clock speed all the way down to 800MHz at idle. As processor loads increase, Cool'n'Quiet ramps the Athlon 64's clock speed back up to 2GHz in 200MHz increments. Apparently, Cool'n'Quiet also lowers the processor's core voltage as its clock speed drops.
When paired with a temperature-controlled processor fan, Cool'n'Quiet could significantly reduce noise levels for idling Athlon 64 systems. Of course, the feature relies on BIOS-level support from motherboard manufacturers.