Don't quite understand how to use PWM fans for my PC

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Killer_Bean420 Dec 26, 2018 @ 4:17pm

I'm looking to change the fans in my PC and Ive seen that PWM fans are supposed to be much better. However I can't find anywhere online that says how many PWM fans I need or how I connect them all. Any info would be greatly appreciated.

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Showing 1-15 of 15 comments

[☥] - CJ - Dec 26, 2018 @ 4:20pm

How many you need/can connect depends on the available PWM fan headers your motherboard has.

PWM simply means being able to control the speed of the fan, either with a fan controller or via your motherboards fan settings in the BIOS.

4pin headers are for PWM

Last edited by [☥] - CJ -; Dec 26, 2018 @ 4:22pm

Garro Dec 26, 2018 @ 4:22pm

PWM fans are connected to the motherboard fan headers or fan controller, you can use fan splitter cables to add more than 1 fan to each header.
There are a few ways you can change your PWM settings such as "SpeedFan" etc which i find to be a piece of crap, best to just set your PWM fan settings within the bios.

Last edited by Garro; Dec 26, 2018 @ 4:23pm

Omega Dec 26, 2018 @ 4:27pm

PWM fans can be more acurately controlled and are capable of spinning at lower speeds.

They are not "better" a PWM fan is just as capable of cooling your PC as a DC fan. But PWM fans can be configured to spin slower and be much more quiet when the system is not under load.

1 fan in the back and 2 in the front is all you need in a gaming machine. Adding more is useless, they only create more noise and pull in more dust.

PWM fans connect to the same headers the DC fans do. The only difference being that the DC fans will only use 3 out of the 4 pins on a PWM fan header and the PWM fan uses all of them. When swapping DC fans with PWM ones you do have to change a setting in the BIOS which tells the PC it's a PWM fan, otherwise it will be opperated like a DC one.

Pretty much any modern motherboard should have PWM fan headers. I don't recall seeing anything modern with only a DC header, asides from in prebuilds with weird motherboards.

Killer_Bean420 Dec 26, 2018 @ 4:37pm

Originally posted by Omega:
PWM fans can be more acurately controlled and are capable of spinning at lower speeds.

They are not "better" a PWM fan is just as capable of cooling your PC as a DC fan. But PWM fans can be configured to spin slower and be much more quiet when the system is not under load.

1 fan in the back and 2 in the front is all you need in a gaming machine. Adding more is useless, they only create more noise and pull in more dust.

PWM fans connect to the same headers the DC fans do. The only difference being that the DC fans will only use 3 out of the 4 pins on a PWM fan header and the PWM fan uses all of them. When swapping DC fans with PWM ones you do have to change a setting in the BIOS which tells the PC it's a PWM fan, otherwise it will be opperated like a DC one.

Pretty much any modern motherboard should have PWM fan headers. I don't recall seeing anything modern with only a DC header, asides from in prebuilds with weird motherboards.

So my motherboard should have 3 PWM fan headers spare (as well as the CPU cooler connector)? Sorry if I'm being dumb I'm just not familiar with this side of PC hardware

Omega Dec 26, 2018 @ 4:43pm

Originally posted by TheREALJohnnyDepp:
Originally posted by Omega:
PWM fans can be more acurately controlled and are capable of spinning at lower speeds.

They are not "better" a PWM fan is just as capable of cooling your PC as a DC fan. But PWM fans can be configured to spin slower and be much more quiet when the system is not under load.

1 fan in the back and 2 in the front is all you need in a gaming machine. Adding more is useless, they only create more noise and pull in more dust.

PWM fans connect to the same headers the DC fans do. The only difference being that the DC fans will only use 3 out of the 4 pins on a PWM fan header and the PWM fan uses all of them. When swapping DC fans with PWM ones you do have to change a setting in the BIOS which tells the PC it's a PWM fan, otherwise it will be opperated like a DC one.

Pretty much any modern motherboard should have PWM fan headers. I don't recall seeing anything modern with only a DC header, asides from in prebuilds with weird motherboards.
So my motherboard should have 3 PWM fan headers spare (as well as the CPU cooler connector)? Sorry if I'm being dumb I'm just not familiar with this side of PC hardware

I don't know. I don't know which motherboard you have.

Killer_Bean420 Dec 26, 2018 @ 4:47pm

Originally posted by Omega:
Originally posted by TheREALJohnnyDepp:
So my motherboard should have 3 PWM fan headers spare (as well as the CPU cooler connector)? Sorry if I'm being dumb I'm just not familiar with this side of PC hardware
I don't know. I don't know which motherboard you have.

I just googled the specs of my motherboard (Gigabyte GA-78LMT) and found this:
1 x CPU fan header
2 x system fan headers
1 x power fan header
1 x front panel header

What is the difference between all these?

Omega Dec 26, 2018 @ 4:51pm

Originally posted by TheREALJohnnyDepp:
Originally posted by Omega:
I don't know. I don't know which motherboard you have.
I just googled the specs of my motherboard (Gigabyte GA-78LMT) and found this:
1 x CPU fan header
2 x system fan headers
1 x power fan header
1 x front panel header

What is the difference between all these?

Which board exactly? There are two different boards with this name,
- Gigabyte GA-78LMT-USB3
- Gigabyte GA-78LMT-S2P

And a million revisions of both.

Killer_Bean420 Dec 26, 2018 @ 4:57pm

Originally posted by Omega:
Originally posted by TheREALJohnnyDepp:
I just googled the specs of my motherboard (Gigabyte GA-78LMT) and found this:
1 x CPU fan header
2 x system fan headers
1 x power fan header
1 x front panel header

What is the difference between all these?
Which board exactly? There are two different boards with this name,
- Gigabyte GA-78LMT-USB3
- Gigabyte GA-78LMT-S2P

And a million revisions of both.

The USB3 one and I have no idea what revision it'd be

[☥] - CJ - Dec 26, 2018 @ 5:27pm

That board has 1 4pin CPU header, and 1 4pin other fan header

So 2 PWM headers in total, 1 of which is the CPU.

All revisions of that board have the same amount of fan headers.

So you are down to the CPU fan, and possibly a front case fan as the header is closest to the front of the case, possibly a top mounted fan as well depending on the length of the cable. As far as PWM fans and the motherboard goes thats all you have access to.
-

PWM doesnt mean its better than a 3pin or molex powered fan, you just have more control over how fast the fan spins.

Last edited by [☥] - CJ -; Dec 26, 2018 @ 5:30pm

Killer_Bean420 Dec 27, 2018 @ 2:13am

Originally posted by ☥ - CJ -:
That board has 1 4pin CPU header, and 1 4pin other fan header

So 2 PWM headers in total, 1 of which is the CPU.

All revisions of that board have the same amount of fan headers.

So you are down to the CPU fan, and possibly a front case fan as the header is closest to the front of the case, possibly a top mounted fan as well depending on the length of the cable. As far as PWM fans and the motherboard goes thats all you have access to.
-

PWM doesnt mean its better than a 3pin or molex powered fan, you just have more control over how fast the fan spins.

I was actually given 3 PWM fans for Christmas (2x 140mm for the the front and 1x 120mm for the rear) so what's my best option?

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Killer_Bean420 Dec 27, 2018 @ 2:35am

Best way to hook up 3 PWM fans to my PC

I was given 3 PWM fans for Christmas but not sure on the best way to connect them all. My motherboard is a Gigabyte GA-78LMT-USB3

#11

[☥] - CJ - Dec 27, 2018 @ 2:50am

Assuming the Case supports the fans you got

You'll need a Y Fan splitter that supports 4pin fans to connect the 2 front fans to the closest fan header
For the rear you can use a molex adapter or another splitter to power the 120mm fan

Would be helpful to know what Case you have and if you have any available fan adapters to power the fans

What fans you got would also be helpful

Last edited by [☥] - CJ -; Dec 27, 2018 @ 2:55am

#12

Midnight Fawn Dec 27, 2018 @ 2:53am

Why do you not just stick with this thread rather than creating more of the same..?

https://steamcommunity.com/discussions/forum/11/1744480967009830750/

#13

Killer_Bean420 Dec 27, 2018 @ 3:42am

Originally posted by ☥ - CJ -:
Assuming the Case supports the fans you got

You'll need a Y Fan splitter that supports 4pin fans to connect the 2 front fans to the closest fan header
For the rear you can use a molex adapter or another splitter to power the 120mm fan

Would be helpful to know what Case you have and if you have any available fan adapters to power the fans

What fans you got would also be helpful

I don't have any adapter's currently.
Case: Corsair Spec 03
Fans: 2x Be Quiet Silent Wings 3 PWM 140mm
1x Be Quiet Silent Wings 3 PWM 120mm

I've heard that it is potentially dangerous to use splitters on the motherboard so would this mean buying a fan hub?

#14

[☥] - CJ - Dec 27, 2018 @ 4:19am

I know of no such issues in doing so
But if you're worried about it you could simply just get Molex to 3pin or 4pin fan adapters

Also -
Front: 2 x 120mm / 140mm (1 included)
Top: 2 x 120mm
Rear: 1 x 120mm (1 included)
Bottom: 1 x 120mm

So you have some options for that case
Just connect them the way they are currently connected

Last edited by [☥] - CJ -; Dec 27, 2018 @ 4:21am

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Date Posted: Dec 26, 2018 @ 4:17pm

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