Question about three pin and four pin PC fans

[PineappleKnight]

Alright, so I'm building a PC for the first time, and it has been relatively simple beyond getting caught up on where some wires plug into the motherboard. However, I have kinda hit a brick wall in where to hook up all of my fans, of all places.

Now, I got my Intel CPU into place, (a Pentium G4560 3.5GHz Dual-Core Processor if it matters, probably not) and then put the included heat sink on it, then took the four-pin cable connected to the heatsink and plugged it into a set of four pins in the top right corner of the motherboard that is designated as "CPU Fan 1". Pretty logical to me. Now I'm left with a three-pin cable wired to the back fan of the case, and a four-pin cable that is wired to the front fan of the case. However, there is only one other set of four pins I can find on this motherboard that can be used to power a fan: it's called "SYS Fan 1".

After some research I've learnt that the best option in this situation is to buy a splitter that allows you to plug in two fans. However, I've been met with some confusion, as I've seen some people mention that you can't have a four-pin fan cable and three-pin fan cable connected to the same splitter. And yet, I've seen others talk about this as if it were not an issue, and they can be connected to one splitter, and it will be fine. So, which one is it? I've seen this splitter be mentioned specifically:
https://www.newegg.com/Product/Product.aspx?Item=N82E16812162026&cm_re=pwm_splitter-_-12-162-026-_-Product&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-VigLink2-_-na-_-na-_-na&cm_sp=&AID=10446076&PID=8167372&SID=j228xf1s0y000a1700053

However, I do not think this splitter will work for my specific problem. I could plug the the three-pin into the four-pin slot, but then the four-pin would have to go into the other, three pin slot, and I don't think that's a good idea. I am beyond uncertain of what I should do at this point, please help.

Here are all of the relevant parts I'm using in my build, I'm pretty sure:
Tower: Zalman Z1 ATX Mid Tower Case
Motherboard: MSI B250M PRO-VD Micro ATX LGA1151
Power Supply: SeaSonic S12II 520W 80+ Bronze Certified ATX

 

[superninja12]

its good you ask ,and you came to the right place,

the cases fans go into the SYS fan pin slots, it doesnt matter if its a 3 pin or a 4 pin.
if its a 4 pin ,its a PWM fan, that means you can control the fan..(or not), otherwise with a 3pin fan the system will automaticly decide the rpms..

edit: solid parts

 

[davidgirgis]

Alright, so I'm building a PC for the first time, and it has been relatively simple beyond getting caught up on where some wires plug into the motherboard. However, I have kinda hit a brick wall in where to hook up all of my fans, of all places.

Now, I got my Intel CPU into place, (a Pentium G4560 3.5GHz Dual-Core Processor if it matters, probably not) and then put the included heat sink on it, then took the four-pin cable connected to the heatsink and plugged it into a set of four pins in the top right corner of the motherboard that is designated as "CPU Fan 1". Pretty logical to me. Now I'm left with a three-pin cable wired to the back fan of the case, and a four-pin cable that is wired to the front fan of the case. However, there is only one other set of four pins I can find on this motherboard that can be used to power a fan: it's called "SYS Fan 1".

After some research I've learnt that the best option in this situation is to buy a splitter that allows you to plug in two fans. However, I've been met with some confusion, as I've seen some people mention that you can't have a four-pin fan cable and three-pin fan cable connected to the same splitter. And yet, I've seen others talk about this as if it were not an issue, and they can be connected to one splitter, and it will be fine. So, which one is it? I've seen this splitter be mentioned specifically:
https://www.newegg.com/Product/Product.aspx?Item=N82E16812162026&cm_re=pwm_splitter-_-12-162-026-_-Product&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-VigLink2-_-na-_-na-_-na&cm_sp=&AID=10446076&PID=8167372&SID=j228xf1s0y000a1700053

However, I do not think this splitter will work for my specific problem. I could plug the the three-pin into the four-pin slot, but then the four-pin would have to go into the other, three pin slot, and I don't think that's a good idea. I am beyond uncertain of what I should do at this point, please help.

Here are all of the relevant parts I'm using in my build, I'm pretty sure:
Tower: Zalman Z1 ATX Mid Tower Case
Motherboard: MSI B250M PRO-VD Micro ATX LGA1151
Power Supply: SeaSonic S12II 520W 80+ Bronze Certified ATX

it is not an issue. it will be fine.

 

[weberdarren97]

its good you ask ,and you came to the right place,

the cases fans go into the SYS fan pin slots, it doesnt matter if its a 3 pin or a 4 pin.
if its a 4 pin ,its a PWM fan, that means you can control the fan..(or not), otherwise with a 3pin fan the system will automaticly decide the rpms..

edit: solid parts

Um... Close but no cigar.

Whether a fan is 3-pin or 4-pin, you can still control the speed.

3-pin fans are controlled by deciding how much voltage is sent over the first two wires, and the third wire reports current RPM back to the controller (likely on the motherboard).

4-pin fans always receive the full 12V on the first two wires, but that doesn't directly power the motor like it does with 3-pin fans. The fourth wire is used to send pulses to the circuitry on the fan in order to control the duty cycle of the fan motor. This means that the motor turns on and off many many times per second, the higher the duty cycle, the higher percentage of activity vs inactivity, meaning the fan spins faster. The lower the duty cycle, the lower the percentage of activity vs inactivity, meaning the fan spins slower. The third wire still reports current RPM to the controller.

I'm left with a three-pin cable wired to the back fan of the case, and a four-pin cable that is wired to the front fan of the case. However, there is only one other set of four pins I can find on this motherboard that can be used to power a fan: it's called "SYS Fan 1".

After some research I've learnt that the best option in this situation is to buy a splitter that allows you to plug in two fans. However, I've been met with some confusion, as I've seen some people mention that you can't have a four-pin fan cable and three-pin fan cable connected to the same splitter. And yet, I've seen others talk about this as if it were not an issue, and they can be connected to one splitter, and it will be fine. So, which one is it? I've seen this splitter be mentioned specifically:
https://www.newegg.com/Product/Product.aspx?Item=N82E16812162026&cm_re=pwm_splitter-_-12-162-026-_-Product&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-VigLink2-_-na-_-na-_-na&cm_sp=&AID=10446076&PID=8167372&SID=j228xf1s0y000a1700053

However, I do not think this splitter will work for my specific problem. I could plug the the three-pin into the four-pin slot, but then the four-pin would have to go into the other, three pin slot, and I don't think that's a good idea. I am beyond uncertain of what I should do at this point, please help.

Here are all of the relevant parts I'm using in my build, I'm pretty sure:
Tower: Zalman Z1 ATX Mid Tower Case
Motherboard: MSI B250M PRO-VD Micro ATX LGA1151
Power Supply: SeaSonic S12II 520W 80+ Bronze Certified ATX

That splitter will work fine for you. Plug the 3-pin fan into the plug that has all four connectors and plug the 4-pin fan into the one that's missing the 3rd connector. This means that the current RPM of the 3-pin fan will be the speed that the motherboard sees as the current speed of each fan. Even without the 3rd pin, the PWM fan will still work perfectly fine. It won't report its RPM, but that's okay because the 3-pin fan is already doing that. The motherboard doesn't care how many fans you plug in or what type they are, as long as you don't draw too much power from the fan headers (two fans is fine) and as long as it's getting feedback from at least one fan because it will view all fans plugged into that header as 1 and will treat them as such.

The motherboard should be able to figure this out and control both fans. If it doesn't and one of them just screams to life at full speed instead of your desired speed, just reply to this thread and I'll guide you through how to get BIOS to treat both fans as if they're 3-pin fans. This will work for both fans because, when no PWM signal is present, PWM fans function just like 3-pin fans.

BTW, I love your username.

 

[PineappleKnight]

That splitter will work fine for you. Plug the 3-pin fan into the plug that has all four connectors and plug the 4-pin fan into the one that's missing the 3rd connector. This means that the current RPM of the 3-pin fan will be the speed that the motherboard sees as the current speed of each fan. Even without the 3rd pin, the PWM fan will still work perfectly fine. It won't report its RPM, but that's okay because the 3-pin fan is already doing that. The motherboard doesn't care how many fans you plug in or what type they are, as long as you don't draw too much power from the fan headers (two fans is fine) and as long as it's getting feedback from at least one fan because it will view all fans plugged into that header as 1 and will treat them as such.

The motherboard should be able to figure this out and control both fans. If it doesn't and one of them just screams to life at full speed instead of your desired speed, just reply to this thread and I'll guide you through how to get BIOS to treat both fans as if they're 3-pin fans. This will work for both fans because, when no PWM signal is present, PWM fans function just like 3-pin fans.

BTW, I love your username.

Ah, okay, that makes sense to me. I went ahead and bought the splitter. A shame I couldn't have foreseen this issue earlier so I wouldn't have to wait for this one little part to arrive to finish building my PC, but oh well. Thank you, and everyone else for the help!

Haha, and thanks! My usernames always seem to come back to being about fruits and metals, so this one was pretty normal to me!

 

[davidgirgis]

That splitter will work fine for you. Plug the 3-pin fan into the plug that has all four connectors and plug the 4-pin fan into the one that's missing the 3rd connector. This means that the current RPM of the 3-pin fan will be the speed that the motherboard sees as the current speed of each fan. Even without the 3rd pin, the PWM fan will still work perfectly fine. It won't report its RPM, but that's okay because the 3-pin fan is already doing that. The motherboard doesn't care how many fans you plug in or what type they are, as long as you don't draw too much power from the fan headers (two fans is fine) and as long as it's getting feedback from at least one fan because it will view all fans plugged into that header as 1 and will treat them as such.

The motherboard should be able to figure this out and control both fans. If it doesn't and one of them just screams to life at full speed instead of your desired speed, just reply to this thread and I'll guide you through how to get BIOS to treat both fans as if they're 3-pin fans. This will work for both fans because, when no PWM signal is present, PWM fans function just like 3-pin fans.

BTW, I love your username.

Ah, okay, that makes sense to me. I went ahead and bought the splitter. A shame I couldn't have foreseen this issue earlier so I wouldn't have to wait for this one little part to arrive to finish building my PC, but oh well. Thank you, and everyone else for the help!

Haha, and thanks! My usernames always seem to come back to being about fruits and metals, so this one was pretty normal to me!

You can still plug in one fan, that'll get you by for now.
You will be able to put everything together, and install Windows and its updates, maybe even some applications.
If you decide to proceed with my suggestion, I recommend plugging in the front intake fan. This will create positive pressure inside of your case, which will escape through any spacing using the path of least resistance.
Then, plug in the rear exhaust fan when you get the splitter.

 

[PineappleKnight]

You can still plug in one fan, that'll get you by for now.
You will be able to put everything together, and install Windows and its updates, maybe even some applications.
If you decide to proceed with my suggestion, I recommend plugging in the front intake fan. This will create positive pressure inside of your case, which will escape through any spacing using the path of least resistance.
Then, plug in the rear exhaust fan when you get the splitter.

Oh, good to know! I may go ahead and do that, just to make sure everything is working properly, since of course I'm a bit eager about that with this being the first PC I've ever built. Wish me luck!

 

[Paperdoc]

weberdarren97 is right. But I'll add a point for clarification. If you mix 3-pin and 4-pin fans using a 4-pin fan Splitter, you MUST arrange that the mobo header you plug into is using Voltage C0ontrol Mode (aka DC Mode). That is the ONLY way to control the speed of a 3-pin fan, and it also works for 4-pin ones. Which fan goes into which output arm of the Splitter does not matter.

In your mobo's manual on p. 14 it says that for both the CPU_FAN header and the SYS_FAN header, you can set each header to use either of these two control modes. So be sure to set the SYS_FAN header to use DC Mode, then SAVE and EXIT from BIOS Setup.

 

[PineappleKnight]

I'm not sure if this thread has expired and I should just start a new one for this topic, but I'll try posting here first. My splitter arrived today, and the three-pin back fan cable fit right into the four pin slot of the splitter no problem. However, the four pin front fan cable is slightly too long to fit in the other, three pin slot of the splitter. In fact, I've tried putting the four pin cable into the four pin slot, and it still won't fit into that one in the same way, as both of the slots are the same length. The four pin cable is only just barely too long to fit into either slot, however. Would it be unwise to shave off one of the sides of the outer plastic casing of the splitter so I can give the four pin cable the little bit of extra space it needs to fit? That's the only way it's going to work at this point.

 

[Paperdoc]

That would be OK. BUT just make SURE you have the connectors turned the right way - there are ridges on the outside SIDE of the female connector that MUST fit into slots in the shell of the male connector.

The other but related option would be to take sandpaper to the two edges of the fan's female connector and thin it down to fit into the Splitter's male output connector shroud.