Sign in with
Sign up | Sign in
Your question

Difference between different Fan connectors on motherboard

Last response: in Motherboards
Share
May 23, 2012 12:29:08 PM

My question is how to connect the case fans to the motherboard.

The case has two intake fans and one exhaust fan, and one optional exhaust fan.

The motherboard has these fan power connectors:

4-pin Chassis Fan Connector (CHA_FAN1)
3-pin Chassis Fan Connector (CHA_FAN2)
3-pin Power Fan Connector (PWR_FAN1)
4-pin CPU Fan Connector (CPU_FAN1)
3-pin CPU Fan Connector (CPU_FAN2)

Per the manual, the Chassis Fan Connectors "support Fan Control".

So which case fans would you connect to the Chassis Fan Connectors, and which case fan would you connect to the Power Fan Connector? Since there are two CPU Fan Connectors, would you everf use one of them for a Chassis Fan?

Here is the motherboard I am looking at. http://www.newegg.com/Product/Product.aspx?Item=N82E168...
a b V Motherboard
a b à CPUs
May 23, 2012 1:05:25 PM

The Chassis fans should be connected to the CHA_FAN headers, but you will be one short. I personally haven't been able to find out what the PWR_FAN header is for exactly, despite alot of searching and reading various forum posts. I don't use it myself and so I can't suggest it to you. You are probably looking at a fan controller, either a multi fan controller for all of them or a single fan controller to connect the third fan.
m
0
l
May 23, 2012 1:17:03 PM

ngrego, is the second CPU Fan Connector of any use (I only have one CPU fan!).

I like things tidy, so this might drive me to get a motherboard that has three Chassis Fan Connectors.
m
0
l
Related resources
a b à CPUs
May 23, 2012 1:22:52 PM

The fan headers have 3 to 4 pins. The common pins are the "Ground" pin, the "Power" pin, and the "sense" pin.

The main difference is going to be the 4th pin known as the "control" pin. This pin can actually automatically control the fan speed. Also known as a PWM (Pulse width modulation) connector. If it is indeed a PWM connector then it must be used with a 4 pin fan aka a PWM fan in order to utilize the PWM functionality.

A 3 pin connector has the ground, power, and sense pin mentioned earlier. Any fan connecter to these headers will run at full speed by default. You are able to look at the RPM of the fan by use of the "sense" pin. Fans using a 3 pin connecter can be controlled manually using software like "fanspeed".

So, to sum up difference.

4 pin header = ability to use PWM fan = automatically adjust fan speed based on whatever variable (typically temperature)
3 pin header = full speed by default = can control by means of software or fan controller

m
0
l
a b à CPUs
May 23, 2012 1:23:53 PM

ratsa said:
ngrego, is the second CPU Fan Connector of any use (I only have one CPU fan!).

I like things tidy, so this might drive me to get a motherboard that has three Chassis Fan Connectors.


2 PWM cpu fan headers would be ideal for a heatsink that used 2 fans like the noctua d14 or any heatsink that could utilize 2 fans for that matter.
m
0
l
May 23, 2012 4:25:38 PM

Which of the three case fans (2 intake one exhaust) need the most control; which one should I run at full speed?
m
0
l
a b à CPUs
May 23, 2012 4:42:49 PM

Depends on the types of fans your using. size, RPM, pwm or not.
m
0
l
May 23, 2012 6:35:39 PM

All three fans are I think the same: 120mm, low RPM. What does pwm mean?
m
0
l
a b V Motherboard
May 23, 2012 9:32:15 PM

PWM is a modulated fan whose speed can be controlled by adjusting the voltage. They have 4 pins instead of 3.
m
0
l
a b à CPUs
May 24, 2012 3:40:41 AM

BVKnight said:
PWM is a modulated fan whose speed can be controlled by adjusting the voltage. They have 4 pins instead of 3.


No that's incorrect. PWM fans receive a constant supply voltage. The speed is actually changed by pulses. So its not adjusting the voltage, its simply turning it on and off at a fast pace.

PWM = Pulse-width modulation
m
0
l
a b V Motherboard
a b à CPUs
May 24, 2012 7:21:08 AM

A mobo with 3 CHA_FAN headers would be ideal but I'm not sure if you cab find any. Even still, I wouldn't spend too much extra on mobo just for the extra fan header. A fan controller would allow you to connect and controll all three and only use up the PWM fan header on the mobo you already have, and controll their speeds too. Fan controllers don't cost too much so it wouldn't be much of a burdon on your budget.
m
0
l
May 24, 2012 2:33:31 PM

skaz said:
No that's incorrect. PWM fans receive a constant supply voltage. The speed is actually changed by pulses. So its not adjusting the voltage, its simply turning it on and off at a fast pace.

PWM = Pulse-width modulation


So with 3-pin fans/ports, the only "control" you have over the fan is to turn it on or off? Or can you still exert some control over its speed?
m
0
l
May 24, 2012 2:36:26 PM

ngrego said:
A mobo with 3 CHA_FAN headers would be ideal but I'm not sure if you cab find any. Even still, I wouldn't spend too much extra on mobo just for the extra fan header. A fan controller would allow you to connect and controll all three and only use up the PWM fan header on the mobo you already have, and controll their speeds too. Fan controllers don't cost too much so it wouldn't be much of a burdon on your budget.



Can fan controllers regulate speed of non-PWM fans, or only PWM fans?
Are fan controllers automatic-and if so how do they get temperature information?

Thanks!
m
0
l
a b à CPUs
May 25, 2012 2:53:16 AM

ratsa said:
So with 3-pin fans/ports, the only "control" you have over the fan is to turn it on or off? Or can you still exert some control over its speed?


Yes you can control a 3 pin fan by the ways I mentioned earlier. Either software like speedfan, or by voltage level by using something like a fan controller. What I was talking about in the message you just responded to was PWM fans which are 4 pin fans.

ratsa said:
Can fan controllers regulate speed of non-PWM fans, or only PWM fans?
Are fan controllers automatic-and if so how do they get temperature information?

Thanks!


Fan controllers are built to "mainly" be used with 3 pin fans not PWM fans. Fan controllers are not automatic you must set the amount of voltage you are feeding the fan.

m
0
l
a b V Motherboard
a b à CPUs
May 25, 2012 7:20:44 AM

That depends on the fan controller you get. There are both types available on the market, either three pin controled by a speed dial or a slider to regulate the speed. But there are also four pin controllers that connect to one four pin header on the mobo and control 4 pin fans.

I picked up this one a while ago but I never used it for some reason, it's still in the box. It can control up to 6 4pin fans from one PWM header!

http://www.coolermaster.com/product.php?product_id=2521

Found one on ebay:
http://www.ebay.com/itm/Cooler-Master-PWM-Fan-Hub-Wind-...
m
0
l
a b à CPUs
May 25, 2012 1:15:58 PM

Like I said, fan controllers are "mainly" to be used with 3 pin fans. Its typical to find 3 pin headers on fan controllers.

I think the OP needs to understand the difference between PWM and non-PWM Fans first. =/
m
0
l
May 25, 2012 9:55:24 PM

I checked my case, and all fans have 3-pin connectors.

What are the recommended settings for case and CPU fans? Is there a tomshardware guide?
m
0
l
a b V Motherboard
a b à CPUs
May 28, 2012 7:27:40 AM

I would keep the CPU fan connected to the mobo don't trust a fan controller to cool your cpu under any circustances. As for the case fans, I would say that the fan speed would be particular to each case. I don't think that there are any guides that can tell yoy what exact speed you should run your fans at, since each case has its own unique layout. Your best bet would be to install the controller and set the fan speed to 50% to start off. Let the pc run for a while to see where the temp will stabilise at. Then do the fine tuning according to the temperature you feel is best for you.
m
0
l
May 28, 2012 10:26:42 AM

I thought the idea was that the controller would vary the fan speed according to the termperature of the CPU, hard drives and/or GPU. Isn't that what you would want?
m
0
l
a b V Motherboard
a b à CPUs
May 28, 2012 2:04:16 PM

Yes but not all work like that! Some have manual speed control.
m
0
l
August 10, 2012 5:09:52 AM

PWR_FAN is for Power Supply if you have a fan connector on your PSU it will help you to regulate the PSU fan speed
m
0
l
!