Case fan replacement tips?

I'm looking for some help with what might be a pretty trivial question. 😵
I'm planning to swap out two fans in my Black Widow case. They’re 120mm units, specifically the A1225M12S model. From what I can tell, they’ve only got 3 pins. Can I just swap them out for some Be quiet! fans that use 4 pins? Or am I going to have to hunt down 3-pin versions—if I do, any recommendations for something decent that won't break the bank? I don't care about LEDs at all since you can't even see them, I just need them to be reasonably quiet.

You can plug a 4-pin fan into a 3-pin header, but don't expect PWM control. It’ll be voltage-based only. If your motherboard lets you tweak voltage on those 3-pin headers via the BIOS—or if you've got a dedicated fan controller—you're fine. Otherwise, it's stuck at a constant 12V running at full blast.

IMO, if your board supports voltage regulation for 3-pin connectors, there's really no need to drop a fortune on high-end fans. Most of them are dead quiet once you get them under 1000 RPM; honestly, they'll be quieter than an average GPU idling at its minimum speed. Noise scales exponentially with RPM.

The Black Widow features its own fan speed regulator, so it doesn't really matter if you're using a 3-pin or 4-pin setup...

Alexander Moore67 said:Black Widow features a fan speed regulator, so whether they're 3-pin or 4-pin doesn't really matter...

You sure that isn't just a PWM controller? How would the stock fans be 4-pin then?

The stock fans are the A1225M12S model, and according to Google, they’re supposed to be 3-pin. But I can never seem to get the speed control working—is that actually why? 😬

Check if they're plugged in properly. See if those fan headers and ports are 4-pin or 3-pin. If they came with a case that has a built-in controller, they really ought to be 3-pin.

BTW, why are you even swapping them out?

One of the front fins somehow snapped off—just one little winglet went missing, so now the whole thing is totally out of balance and scrapes against the ground every once in a while. To make matters worse, that rear air exhaust vent won't spin at all anymore; I haven't the slightest clue what caused it to quit.

Strip them down. Swap the connection from the one that isn't spinning with the one that's shorting out—just to be absolutely sure the issue lies with the fans themselves. Check all your connections and see if you can actually control the speeds manually.

Man, I can barely even turn this rear one by hand—it keeps catching on something, like it’s just stuck.

Just swap all three. They probably burned through their own budget on them. Also, Molex is used for the fan speed regulator—once you pop the front panel off, you can adjust it between three different speeds.

jadetrucker43 said:The rear one is barely turning by hand; I think something is catching inside.

Either the ball bearing is shot, or it’s just seizing up—you can actually feel it grinding when you try to spin it manually. I ended up getting a replacement. Mine was originally a 4-pin from the case, but the store only had 3-pin versions in stock. Since my motherboard has a dedicated sysfan header that supports it, I just plugged it straight in. If you find yourself in that situation, I guess just double-check the cable length before you buy.

Finally swapped out all three fans for Noctua NF-P12 redux. I actually managed to wire them correctly this time—hooked them straight to the Molex from the PSU and the case fan controller—though let’s be honest, they’ll probably just sit at max speed the whole time anyway. Everything is working perfectly, though, and the best part? It’s dead silent. 👍