Difference between different Fan connectors on motherboard

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=N82E16813157301
21 answers Last reply
More about difference connectors motherboard
  1. 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.
  2. 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.
  3. 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
  4. 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.
  5. Which of the three case fans (2 intake one exhaust) need the most control; which one should I run at full speed?
  6. Depends on the types of fans your using. size, RPM, pwm or not.
  7. All three fans are I think the same: 120mm, low RPM. What does pwm mean?
  8. PWM is a modulated fan whose speed can be controlled by adjusting the voltage. They have 4 pins instead of 3.
  9. 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
  10. 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.
  11. 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?
  12. 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!
  13. 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.
  14. 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-Rider-Neuro-PWM-Distributing-Technology-/190680523481?pt=UK_Computing_Case_Mods_Stickers_Decals&hash=item2c6571e2d9
  15. 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. =/
  16. 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?
  17. 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.
  18. 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?
  19. Yes but not all work like that! Some have manual speed control.
  20. 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
  21. sorry for doing this necro post but i dont wanna bother you all in open a new thread for just a single dumb question.

    Can i connect more than 1 PWM fan? im goin to put some fans to my case, like 3, but i dont know if 3 extra PWM(besides the cpu cooler) will cause problems, like no reading on the speeds.
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