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Controlling 3-Pin Fans With the Motheboard Fan Headers

post #1 of 4
Thread Starter 
Possibly a dumb question, but I have owed a fan controller for as long as I can remember.

Can you control the RPMs of 3-pin fans on motherboards, obviously depending on whether the BIOS and/or software allows it. I am going to get a Z87 motherboard and hope to do away with the fan controller but only if I can easily control my fans off the motherboard.

How about using all PWM fans and connecting them via splitter and plugging that into the CPU header, would that work? I am guessing this would be a bad idea if you are using different fans?
post #2 of 4
I think you can only control 4 pin fans via motherboard PWM fan control.
You can use all PWM fans and connect them via a splitter to the CPU header but you have to be careful not to exceed the maximum wattage the motherboard can feed to those particular pins. Depending on how many fans you have this may be untenable.
post #3 of 4
I have an old Asus motherboard from 2009. I have the option to control fan speed using three presets: silent, optimized, and high performance. I cannot individually control each fan speed though. So meaning the silent setting sets all chassis fan headers to 5V (?).

And yes, a splitter will work for PWM. Probably don't want to exceed 1 amp on the header though.
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POS
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post #4 of 4
My Asus board comes with 2 CHA Fan 4-pin headers.
These headers control both 3-pin and 4-pin fans by DC.

The CPU Fan is a PWM header that controls only 4-pin fans.
Any 3-pin fans will run at full blast.

From all I've heard about Asus boards, the CHA Fan 4-pin aren't PWM headers.
The CPU Fan is the most likely the only PWM header.

I've tested the Akasa 2-way and 5-way splitters on my board.
The 5-way splitter draws power from the psu.

The speed control using splitters that draw power from the psu will work only with PWM headers.
So the speed control will work in the CPU Fan with 4-pin fans but any fan will run at full blast in the CHA Fan.

The speed control using the 2-way splitters will work fine by PWM or DC.
The CHA Fan can control both 3-pin or 4-pin fans using the 2-way splitter.
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