Case Fan Plug Does Not Match Sys Fan

Discussion in 'Computer Cases, Power Supplies and Cooling' started by Freerunner, May 13, 2018.

  1. Freerunner

    Freerunner Member

    Messages:
    588
    I'm trying to connect the case fans to my mb, but the female end from the fans only has accepts 3 prongs and the mb sys fan connection is 4 prongs. How do I handle this? The 2 items are:

    GIGABYTE GA-AB350M-Gaming 3 (rev. 1.0) AM4 AMD B350 SATA 6Gb/s USB 3.1 HDMI Micro ATX AMD Motherboard

    ROSEWILL ATX Mid Tower Gaming Computer Case, Gaming Case with Blue LED for Desktop / PC and 3 Case Fans Pre-Installed, Front I/O Access Ports (CHALLENGER)
     
  2. OmniDyne

    OmniDyne Member

    Messages:
    81
    The 3 pin fan connector will work with the 4 pin motherboard connector. You simply line up the tabs. One motherboard pin will simply not be utilized.

    The photo looks similar to the connector for your case fans, right?
     

    Attached Files:

  3. Freerunner

    Freerunner Member

    Messages:
    588
    But won't I lose some functionality? If I am reading the instructions right for the mb, the pins represent the following; ground, voltage speed control, sense, and pwm speed control.
     
  4. OmniDyne

    OmniDyne Member

    Messages:
    81
    You'll lose PWM.

    Actually technically you're not losing anything, because fans with 3 pin connectors aren't capable of PWM. They'd have to be 4 pins and PWM capable.

    All this means is that the fans will run full speed, and you will not be able to control their speed.

    However, some motherboards are capable of controlling fan speed through 3 pins via voltage control, although that's usually on more expensive motherboards.
     
  5. Freerunner

    Freerunner Member

    Messages:
    588
    OK, thanks
     
  6. OmniDyne

    OmniDyne Member

    Messages:
    81
    It appears your motherboard is voltage control capable.
     
  7. Freerunner

    Freerunner Member

    Messages:
    588
    One last question about the fans. The mb can handle 3 fans (including the cpu). However I have 3 fans in the case and cannot figure out how to connect the third one (it also has the 4 pin female as well as a larger 4 pin female, sorry I don't know the name of the cables, see picture). Where do I connect this fan?
     

    Attached Files:

    Last edited: May 13, 2018
  8. johnb35

    johnb35 Administrator Staff Member

    Messages:
    40,441
    Some fans come with the 3 pin and a 4 pin molex connector. The molex is used when you don't have a fan header on the motherboard. So in your case if you have a motherboard header to attach it to then you don't use the 4 pin molex.
     
  9. Freerunner

    Freerunner Member

    Messages:
    588
    Nowhere on the mb can I see a spot for the molex. Any suggestions?
     
  10. johnb35

    johnb35 Administrator Staff Member

    Messages:
    40,441
    If you don't have enough headers on the motherboard, you'll need to use a molex from the power supply.
     
  11. OmniDyne

    OmniDyne Member

    Messages:
    81
    You'll see a connector similar to this one coming from the power supply.
     
  12. Freerunner

    Freerunner Member

    Messages:
    588
    Yep, got it, thanks
     

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