# 4 Pin Case Fan question



## downtick (May 17, 2006)

I have a few 4 pin case fans here I want to put inside my new build...i connected them to an external 3 pin adapter that powers on with a molex just to check out the noise and airflow..does anyone know do fans default to max rpm without a speed controller being used? the fan moves a lot of air, but i think it is a the max rpm because the thing is so loud! I know the fan has a range of 600-2000 rpm. If i do use it in my new build and connect it to a 4 pin on my mother board, will the bios adjust the case fan rpm automatically to lower speeds and thus lower noise as soon as computer is powered on? I don't want a jet engine inside my computer! I love the air flow, but not worth it at the noise level!

Thanks!


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## linderman (May 20, 2005)

YES without a controller the fan will run at max speed

and the motherboard "can" adjust the fan speed depending on which fan header you use on the motherboard

the SYS header is the motherboard temp and that one will raise and lower the fan rpm's as needed

but the CHA (chassis fan header) will not, that one will run at 100%

best bet for you is an external fan controller like this one

http://techgage.com/article/zalman_zm-mfc2_fan_controller/

or

http://en.kioskea.net/guide/645360352-akasa-akasa-lcd-fan-controller-for-5-25-inch-bay


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## downtick (May 17, 2006)

I have 5 headers on my mobo...1 cpu, 2 fan chasis and 2 optional fan...from what i get in my manual, the fan speed can be adjusted by the bios for the cpu and the 2 chasis fans based on the temps...if i want the optional fans to be able to adjust, i need to connect 2 thermal sensors that are located right next to each of the optional headers.

but what if i disable this in the bios (its called Q-fan control with my asus board) and go with speedfan.. my question is will all fans run max until speedfan kicks in (once windows has booted) and adjusts the speeds to the settings i pre-determined?


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## linderman (May 20, 2005)

downtick said:


> I have 5 headers on my mobo...1 cpu, 2 fan chasis and 2 optional fan...from what i get in my manual, the fan speed can be adjusted by the bios for the cpu and the 2 chasis fans based on the temps...if i want the optional fans to be able to adjust, i need to connect 2 thermal sensors that are located right next to each of the optional headers.
> 
> but what if i disable this in the bios (its called Q-fan control with my asus board) and go with speedfan.. my question is will all fans run max until speedfan kicks in (once windows has booted) and adjusts the speeds to the settings i pre-determined?


 <<<< that is correct


you will soon find motherboards dont perform fan speed controlling very well 

the cpu fan speed comes from the sensor within the cpu thats why that one works so efficiently

you best bet is the fan controller which you can control manually or in auto mode at your pre-determined temp & fan speed


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## downtick (May 17, 2006)

i agree with you..my only problem with fan seed controllers is that all my 4 fans are 4 pin fans and these controllers only control 3 pin fans, with the exception of the zalman that controls only 1 4 pin fan...any ideas? do i need to just get rid of my 4 pin fans?


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## linderman (May 20, 2005)

fans do not have to have all four pins connected to have fan spped control

http://www.bigbruin.com/reviews/xtunner/

quote

*Within the packaging is three, 4 pin pass through to 3 pin adapters,* one key ring for the remote control, one 4 pin Molex extender, and an adapter to allow you to still monitor fan speed from your motherboard. The 4-pin to 3 pin adapters are the high quality kind in that the pass through 4-pin part is one piece and not 2 separate connectors. The speed monitor adapter is a great addition, allowing the yellow wire from the fan to end up plugged back into the motherboard for programs like Mother Board Monitor or more importantly, to keep the ability of some BIOS’s automatic shutdown on CPU fan failure. I’m not quite sure why you would ever need to keep the 1/8” thick remote on your key chain, but they have included a rather nice spring clip/split ring unit for just that purpose.


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