How can I use pwm with 3 pin fans?

[DarkDubzs]

If I buy cheaper priced 3 pin case fans can I somehow use them so that the motherboard pwm automatically controls their speeds like normal 4 pin pwm fans? I only have one available 4 pin header on my motherboard besides the CPU fan header, so I would probably have to use like a pwm hub or connect the fans together to run off one pwm signal if that's possible. So how can I achieve this goal? Any help and feedback is greatly appreciated.

 

[Deuce65]

What motherboard do you have

 

[DarkDubzs]

What motherboard do you have

An MSI FM2-A75MA-E35

 

[Deuce65]

You should be able to use the 4 pin header sysfan1. the fourth pin doesn't do anything.

 

[DarkDubzs]

You should be able to use the 4 pin header sysfan1. the fourth pin doesn't do anything.

No, I'm asking if I can have the motherboard control connected 3 pin fans with pwm signals?

 

[Deuce65]

Well no, you don't have pwm fans so of course you can't use pwm speed regulation! That is why I suggested using the system header, it will control speed via voltage control.

 

[DarkDubzs]

control speed via voltage control.

do you mean via fan speed controlling software? Like speedfan or something?(although i highly do not recommend downloading speedfan)

 

[Deuce65]

control speed via voltage control.

do you mean via fan speed controlling software? Like speedfan or something?(although i highly do not recommend downloading speedfan)

No, you can use the standard speed control software that comes with that motherboard. I don't recall what MSI calls it. Or you can go into the bios and set it that way.

 

[DarkDubzs]

control speed via voltage control.

do you mean via fan speed controlling software? Like speedfan or something?(although i highly do not recommend downloading speedfan)

No, you can use the standard speed control software that comes with that motherboard. I don't recall what MSI calls it. Or you can go into the bios and set it that way.

i have no idea how to do that..:lol:

 

[Deuce65]

Well it is exactly the same as if you were using a pwm fan
I don't know how MSI bios or software looks but im sure if you go into the bios you will be able to find it under something like monitoring. Or just download your manual and im sure it will tell you. Or install the software that came on the disk that came with your board. If you lost it, I'm sure you can download it from MSI.

 

[DarkDubzs]

Well it is exactly the same as if you were using a pwm fan
I don't know how MSI bios or software looks but im sure if you go into the bios you will be able to find it under something like monitoring. Or just download your manual and im sure it will tell you. Or install the software that came on the disk that came with your board. If you lost it, I'm sure you can download it from MSI.

Well im familiar with the BIOS, its uefi so very user friendly, its just that i never nderstood what to set it to under the fan control section part. Ill look into it more. thanks

 

[DarkDubzs]

Actually, do you know if it would still work with like a 4 or 3 pin hub to plug in more fans?

 

[Cunning linguist]

You cant use pwm on 3 pin fans period. You cant even have it run at a reasonable speed! oh man 8 corsair sp fans at max speed is insane. I think my solution would be to use a transistor that controls a mosfet that controls the fans from a hub. 4 pin fans are also reportedly less reliable because the thing that receives the pwm signal is a tiny transistor so a discrete transistor means it can be bigger, and if its destroyed, replaceable.

solution would be to connect pin 4 to base and put the other legs as a wire between the fan and the mobo