cha_fan

Hey everyone. So, I grabbed this case fan to help pull some air into my rig, but now I’m dealing with a bit of a headache. The thing is way too loud—like, obnoxious levels of noise—and I can't find a way to dial it back. I've already poked around in the BIOS and tried messing with SpeedFan, but nothing seems to stick. It's just a standard mid-sized fan, and my system definitely sees it; when I jump into the BIOS, I see it listed under the CHA FAN header, and the RPM is just... massive. HOW DO I SLOW THIS THING DOWN???

Motherboard: N/A

To actually control the fan speed, you're going to need a PWM-enabled fan with a 4-pin connector.

The chassis fan is plugged directly into that motherboard header. Go into your BIOS and see if there’s a setting for that CHA_FAN—something like 30%, 40%, or 50% PWM—and try dialing it back. If you don't have that option, your only real move is playing around with the voltage. It sounds more intimidating than it actually is; just drop the voltage to 5V or 7V to slow down the RPM.

I tried digging through my BIOS to find it, but there’s nothing there... just settings for the CPU. I checked the CPU fan too, and it's hooked up to those three pins, so I can tweak the speed using Fan Expert, I guess. Can anyone walk me through how to actually lower the voltage? Like, is there some kind of software I should be using for that?

What exactly is the deal with the CPU fan? If it’s got a 3-pin connector, you should be able to control the speed.

Regarding that mode, there are two ways to go about it. Using a resistor:

Or without one, just by swapping the wires:

Which you can honestly do yourself just by moving the connector pins. All you need is this:

Instead of feeding the standard +12V to the two pins the fan actually needs to spin, you combine other wires to get 7V (you don't connect +12V to ground; you bridge +12V and +5V to get 12-5=7V) or +5V and ground to get 5V.



To figure out which pins your specific fan needs, just try connecting something—like a 4.5V battery—just to see it spin. It’ll only work with one specific combination of two wires; the third wire is just for speed control, which you won't be using anyway.

I just grabbed a photo from Hilton; their cables are outrageously overpriced. I used to pick mine up at Links for pennies when they actually had them in stock. Check Chipotle... Honestly, any local repair guy or TV tech would probably do this for you in exchange for a beer...