Specs on AMD's Cool'n'Quiet
http://www.amd.com/us-en/Processors/...E13339,00.html

The skinny of the problem is my new 64-bit Sempron 3000+ supports it but the AMD supplied CPU fan only has three pins. To enable variable speed fan in BIOS I need four pins. So I really only have half of Cool'n'Quiet working, the frequency scaling between 1GHz and 1.8GHz. I already have variable speed fans in PSU and front of case (self-controlled via temp sensors). If I could just get the CPU fan to slow down would truly be a quiet PC. Right now it's only cool. hehe

Anyone know where I can get one without buying another boxed AMD CPU? Apparently they're included with the more expensive processors. I just didn't get one with my Sempron.

I searched ebay for replacement heasink/fan combos and none claimed compliance with AMD's spec.

Not to be confused with a 4-pin molex power connector. This one attaches directly to the mobo and is strictly for CPU. Apparently the proper name is a PWM, which is short for pulse width modulation. Found a 92mm Evercool on ebay pretty cheap: http://cgi.ebay.com/EVERCOOL-92mm-PW...QQcmdZViewItem

Unfortunately I need a 70mm for my AMD heatsink, so couldn't use it.

What is your motherboard's brand and model. Then I or someone else can tell you that it may or may not be needed. If it ain't broken, don't fix it.

Having a power supply that you can control its fan speed does not work well. If you want completely noise free, Seasonic S12 power supplies are noiseless and they are more efficient than other power supplies.

You can get Zalman's Fan Mate 2 to connect between the CPU fan and the motherboard. One disadvantage of using this is Cool 'n Quiet have to be disabled, so the fan can predictively turn on upon power up.

If you need that many fans, something is wrong with your setup. Semprons do not need that many fans. They only consume 35 watts of power, so just a heatsink (no fan) can dissipate the heat with out any problems.

There's always room for improvement. So if it ain't broke, get off your fat ass and improve it.

Philosophical differences aside, I still need a 70mm fan with four pins, the fourth being for PWM.

The motherboard I'm plugging it into is irrelevant.