4 pin chassis fan control

Greard

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Jul 20, 2011
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Hi, I"ve been reading the info about 3 pin vs 4 pin fans and speed control and I think I have learned a lot, but I still have a little confusion.
My motherboard (ASUS P8H77-I) has 4 PIN header for the CPU with pins for PWM, IN, PWR, GND. So i get that this allows the mobo to control speed with PWM.
But the CHA fan header pins are +5V, IN, PWR, GND. Does this mean that the speed of a 4pin fan could be controlled by voltage regulation ? Are some 4pin fans PWM and some for voltage regulation ?
Thanks.
 

jnkweaver

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Nov 11, 2011
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That is how your mb controls your fans, with voltage regulation. The fan is a simple DC motor, lower voltage it spins slower and higher voltage it spins faster.

Actually a PWM fan controls it with full voltage at a certain pulse. That being said yes you can control your fan with voltage. That is how most fan controllers work.
 
Hello... 4 wire/pin fan, will give tach feedback, the speed of the fan will be readable in your BIO's and other reporting software... Also will tell your BIO's if your Fan is not turning, and can give you an alert if there is a Fan/cooing problem.