# BIOS and system fan control



## paulhol (Aug 17, 2006)

I'm running a Gigabyte DS4 motherboard, and i have two 120mm case fans connected through a 3 way splitter to the single system fan socket on the board. The mobo came with BIOS F2 and the fan speed adapted to temperature and was barely audible, but ever since i upgraded to BIOS F6 one of the case fans goes straight to full power on startup and stays that way, making a helluva noise as a result. Any ideas? Everything is set to default in the BIOS still


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## jflan (May 29, 2005)

paulhol said:


> I'm running a Gigabyte DS4 motherboard, and i have two 120mm case fans connected through a 3 way splitter to the single system fan socket on the board.


 I would not want to run this much power through a mobo fan header. If you want auxilliary fans, connect directly to your power supply via a speed controller and then dial-in the noise/cooling sweet spot. If you have a free mobo header, you can drop in an RPM signal and watch RPM, temp and listen as you dial-in. Choose a fan with RPM signal to do this.


> The mobo came with BIOS F2 and the fan speed adapted to temperature and was barely audible, but ever since i upgraded to BIOS F6 one of the case fans goes straight to full power on startup and stays that way, making a helluva noise as a result. Any ideas? Everything is set to default in the BIOS still


 Sometimes BIOS updates are buggy. I would ask Gigabyte what's up with this new BIOS.
If no overall gain from F2 I would go back.


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## Doby (Jan 17, 2006)

> I would not want to run this much power through a mobo fan header. If you want auxilliary fans, connect directly to your power supply via a speed controller and then dial-in the noise/cooling sweet spot. If you have a free mobo header, you can drop in an RPM signal and watch RPM, temp and listen as you dial-in. Choose a fan with RPM signal to do this.


Wow, good advice jflan! I don't like running any case fans thru the mobo let alone with a splitter and alway connect case fans thru the psu direct.

Very good advice!


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## Tumbleweed36 (May 14, 2005)

Hi,

I also agree with my team mate jflan. Good job on this analysis. While I run two 120mm fans, I just don't use the motherboard or sensor to run them, although that feature is available to me with this board. 

I run both fans off my power supply (use 3 speed Antec Fans) and run them only at the slowest speed. That way, no loud fans, no changing speeds or noise level, adequate cooling, the opportunity to move them to a higher speed if needed (never do), and they do the job since my rig runs at-rest at 29c.


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