# 3 pin chassis/pwr fan plug on motherboard



## Morbo (Jan 24, 2007)

Hi,

In process of building my first machine. A quick question. I have an Asus M2N E SLI AM2 mobo. There are two 3 pin plugs sticking up on the motherboard. The manual lists them as chassis and power fan connections. Now, I bought 2 120mm fans for my case, and installed them. Noticed the fans only come with standard 4 pin molex power connectors. So I guess they get connected straight to the power supply. Does this also mean they are "dumb", meaning the mobo can't control their speed? So what's the difference between hooking the fans straight to the power supply vs hooking it to the mobo with the 3 pin?

thx


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## Doby (Jan 17, 2006)

IMHO its always best to connect case fans to the psu, yes the 4 pin molex do this, it takes stress off the board. Yes they will be dumb in that you can't ajust the speed but you can get a fan controller that mounts in a drive bay to controll them


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## linderman (May 20, 2005)

all you need to get is a molex to three pin header adapter to convert the plug so you can connect one of them to the motherboard which will control the fan speed.

or you can get a 5.25 inch drive bay fan speed control as Doby has suggested


the Powerfan is suppose to be connected to the powersupply 3 piun connector, if this is NOT conencted you cant monitor your PSU fan speed nor get PSU unit temperature which are normally reported by AUX temp reading ??


in my humble opinion you would be FAR better served to return the two fans you got and get 2 of these, they are cheap at $12.00 each and they have manual speed control knobs and have the three pin & molex connectors both!!

& the TT fans are *5000 rpm* too; most common 120mm fans sold are 1700 rpm

win - win situtaion & cheaply too!

http://www.newegg.com/Product/Product.asp?Item=N82E16811999145

http://www.frozencpu.com/products/2513/fan-214/Thermaltake_120mm_Smart_Case_Fan_II_A2029.html


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