[SOLVED] Simple question: where do I plug my cooling fans in?

Jan 3, 2021
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  • I have some case cooling fans, link here
  • I have a EVGA Supernova B2 750W, link here
  • I have an old motherboard, link here
Where do I plug the cooling fans into? Do I plug them somewhere into the motherboard or directly into the PSU? I can't really tell what connector the fans use. It shows a 3 pin and 4 pin cable in one of the images, but I'm really confused what type of connectors they are. I also can't find information/specs about the connectors on this motherboard. Additionally, the PSU's peripherals are labeled "perif" which is making it hard for me to understand if the fans' connectors will fit into them.

I'm just really confused overall on how to get this to work, so any advice would be highly appreciated!

P.S. just as an aside, I'm wondering if it's possible to turn off the fans' RGB lights. I can think of two possibilities: a) use the 3 pin instead of the 4 pin, since the extra pin is used to supply the LEDs with power? and b) disconnect the lights somehow, which would require me to open up the fan I think.
 

Paperdoc

Glorious
Ambassador
You and other posters are correct in locating those two 3-pin case ventilation fan headers. They should be used for your new three fans, although you will need at least one Splitter to connect two fans to one of those headers. A simple Splitter like this

https://www.amazon.com/StarTech-com-12in-Power-Splitter-Cable/dp/B002DY7M1G/ref=sr_1_8?dchild=1&keywords=fan+splitter&qid=1614824511&sr=8-8

would do. That's a 3-pin model. Any 4-pin Splitter also can be used. Or you could get a Splitter with THREE output "arms" and connect all three fans to one of your two headers. The fan specs say each pulls at max 0.18 A, and most mobo headers can supply up to 1.0 A max, so even three of these on one header is OK. These are so inexpensive, you pay too much to have then shipped from most on-line sources. But they also should be easy to find in any local computer parts shop.

Forget the larger 4-pin Molex male connectors on your fans' wires. Those are only to use to connect directly to a PSU female Molex output, which is not a good option and should NOT be done when you connect to mobo headers. But just for your info, the PSU you have is called a Modular design. It has sockets on its side of various types, and comes with cables that you plug into those. You NEVER plug into those sockets wires from your mobo or fans, etc. Instead you use ONLY the cables that came with the PSU, and THOSE CABLES have the actual output connectors for different uses, like a main one to your mobo power connector, and several SATA power connectors, etc. The sockets labelled "Perif" have a cable for them that can provide SATA and / or Molex power outputs.

The fans you bought have several LED's of different colours mounted in their frames. They have no separate cable to supply power to the lights, and NO way to control or change what they do - their display is fixed. They are simply wired in parallel with the fan motors, so they light up whenever the fan has power. Their brightnesss may decrease when the fan is running slower.
 
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looking at this you'll probably need a splitter.

the 3pin connector on the fans is for the fan itself. it plugs into a fan header on the mainboard. see that 4 pins between RAM and CPU socket? that's a fan header. Probably for the CPU fan this one. I spot another one where the IO shield is at the VGA port and one in the corner on the other side, South-East corner on the picture.
the 4pin of your fans look like a molex. your PSU should come with one I think. it will be the only one fitting to the 4pin molex connector of your fans, there could be more than 1 on the cable. don't try to connect it to the SATA power cable.

not sure you can disable the lights completely. according to amazon you're not to use both molex and the fan header at the same time. if connected to molex the fans will run full speed as they get max power. keep that in mind. no information about the LED and the connection. since it's 3pin fans the LED would depend on the power supplied. so slower fan speed -> less lights. but there should be some documentation provided with the fans.
 
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Eximo

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The large 4-pin would go to the power supply. This would run the fans at 12V, full speed. As indicated, you choose one or the other, not both.

3-pin connector would go to the motherboard. Your board has three fan headers. One by the memory (4-pin, which is for the CPU fan, but will accept a three pin fan), One 3-pin header by the rear I/O, and one down by the front panel connector.

As for the RGB, they didn't go into much detail. So I assume those will just be ON, possibly cycling through colors. They specifically mention there is no remote or controller and to not plug them into an RGB header.
 
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Eximo

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looking at this you'll probably need a splitter.

the 3pin connector on the fans is for the fan itself. it plugs into a fan header on the mainboard. see that 4 pins between RAM and CPU socket? that's a fan header. Probably for the CPU fan this one. I spot another one where the IO shield is at the VGA port and one in the corner on the other side, South-East corner on the picture.
the 4pin of your fans look like a molex. your PSU should come with one I think. it will be the only one fitting to the 4pin molex connector of your fans, there could be more than 1 on the cable. don't try to connect it to the SATA power cable.

not sure you can disable the lights completely. according to amazon you're not to use both molex and the fan header at the same time. if connected to molex the fans will run full speed as they get max power. keep that in mind. no information about the LED and the connection. since it's 3pin fans the LED would depend on the power supplied. so slower fan speed -> less lights. but there should be some documentation provided with the fans.
To be clear, both connectors are for fan power, but only one at a time. The effect of using the fan headers and molex connector at the same time would be to plug the power supply into the motherboard fan headers, THIS IS A BAD THING.

LEDs will likely maintain their brightness as they are going to be much lower voltage, lower the voltage, the better for the load on the resistor, LED will always drop the same voltage (varies a little by temperature, but not that important here)
 
Reactions: donutcoffee
Jan 3, 2021
30
1
35
0
Thank you for both of your replies.
To be clear, both connectors are for fan power, but only one at a time. The effect of using the fan headers and molex connector at the same time would be to plug the power supply into the motherboard fan headers, THIS IS A BAD THING.

LEDs will likely maintain their brightness as they are going to be much lower voltage, lower the voltage, the better for the load on the resistor, LED will always drop the same voltage (varies a little by temperature, but not that important here)
Thanks, that clears up the confusion I had from your answer!

I just have two remaining questions, sorry for being such a noob at this.

1. You and the other person mentioned there are three fan headers, one of which is for the CPU. I see the 4 pin CPU fan header on the motherboard (1), but where are the others? I tried marking them 2 and 3. 2 looks like a 3 pin fan header but I'm not sure about 3. The resolution kind of sucks



2. You say the 4 pin molex will fit into the PSU, but which one is that? The PSU in question has some 2x3 pin connectors labeled "perif" which wouldn't fit because they're too small to fit a 1x4 pin connector.
 

Paperdoc

Glorious
Ambassador
You and other posters are correct in locating those two 3-pin case ventilation fan headers. They should be used for your new three fans, although you will need at least one Splitter to connect two fans to one of those headers. A simple Splitter like this

https://www.amazon.com/StarTech-com-12in-Power-Splitter-Cable/dp/B002DY7M1G/ref=sr_1_8?dchild=1&keywords=fan+splitter&qid=1614824511&sr=8-8

would do. That's a 3-pin model. Any 4-pin Splitter also can be used. Or you could get a Splitter with THREE output "arms" and connect all three fans to one of your two headers. The fan specs say each pulls at max 0.18 A, and most mobo headers can supply up to 1.0 A max, so even three of these on one header is OK. These are so inexpensive, you pay too much to have then shipped from most on-line sources. But they also should be easy to find in any local computer parts shop.

Forget the larger 4-pin Molex male connectors on your fans' wires. Those are only to use to connect directly to a PSU female Molex output, which is not a good option and should NOT be done when you connect to mobo headers. But just for your info, the PSU you have is called a Modular design. It has sockets on its side of various types, and comes with cables that you plug into those. You NEVER plug into those sockets wires from your mobo or fans, etc. Instead you use ONLY the cables that came with the PSU, and THOSE CABLES have the actual output connectors for different uses, like a main one to your mobo power connector, and several SATA power connectors, etc. The sockets labelled "Perif" have a cable for them that can provide SATA and / or Molex power outputs.

The fans you bought have several LED's of different colours mounted in their frames. They have no separate cable to supply power to the lights, and NO way to control or change what they do - their display is fixed. They are simply wired in parallel with the fan motors, so they light up whenever the fan has power. Their brightnesss may decrease when the fan is running slower.
 
Reactions: donutcoffee

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