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Can someone explain the significane of fan rpm reporting/monitoring?

By macx
Oct 22, 2005
  1. On an ATX board (mine is an ASUS P4C800-E Del) there are 3 connectors for fans, one of which is ordinarily for
    the CPU fan, but I understand they have a common power feed so any fan be hooked to any one of them.

    Now, first, is it good or not good to hook fans to the board? I read a post somewhere suggesting it wasn't.

    Second, does the board control the rpms of the fans
    based on heat, or ??? Or does it just report the rpms
    to a monitor if you have one.

    Trying to get this all learned so I can adequately
    cool my new system. I know I need more case
    fans from what info I've dug up recently -
    but would like to know about this rpm thing.

    Thanks!!
     
  2. Rik

    Rik Banned Posts: 3,814

    It will depend on the chipset on your motherboard as to whether its capable of speedcontroling fans, most dont.
    Personally i prefer to use a fan controller to run all fans, I have a CoolerMaster Aerogate II to which i connect all my fans as it will control them according to temperature and gives of an alarm sound if a fan fails on me.
    Its entirely up to you how you set your system up, but , some mobos cant handle putting too much power through them for fans, whereas a fan speed controller will tell you in the instruction manual how much it can handle.
    As an example, i have gone for overkill on the cooling front, my aerogate has 4 outputs and I'm using more fans than that, so 2 of then are both connected to one output (i did check power consumption before doing this) and all works fine.
     
  3. macx

    macx TS Evangelist Topic Starter Posts: 712

    Although I believe mine is set up to do that (am at work,
    don't have the info in front of me - ASUS P4C800E-Del)
    I've also read about limitations on supplying fan power
    thru any board.

    I'll look into that fan controller thing - sounds like a safer way to go.

    Thanks for the info!
     
  4. macx

    macx TS Evangelist Topic Starter Posts: 712

    OK - now for a fan controller,
    do I need what's called
    "rpm sensing" fans?

    What's the "rpm sensing" thing
    all about, and do I need it -
    like to allow a control or monitor
    to show the rpm?

    Or will a "regular" fan work
    (one that isn't termed
    "rpm sensing")?

    Thanks!!

    Sooner or later, I'll get ALL
    this figured out!
     
  5. Rik

    Rik Banned Posts: 3,814

    Rpm sensing fans have an extra yellow wire on them that standard fans don't have, this is the sensor output. You don't have to use fans with sensors on a fan controller but it is easier for 2 reasons.
    1 - Obviously, using a fan with a sensor means that the fan controller will show you what speed the fan is running at.
    2 - Most fans with sensors come with a small 3 pin plug that will fit to the fan controller with no rewiring required. Whereas, some standard fans come with molex (standard power) connectors which would require rewiring.

    The fan controller doesn't need to have a fan with a sensor on it as it will still control it, however, with no speed output, it cant tell that a fan is present and will say 0000 on the speed display.
     
  6. macx

    macx TS Evangelist Topic Starter Posts: 712

    NOW it's starting to come together!! :approve:

    I was just aware of bits and pieces but not how
    the whole thing worked together or what
    some of the terminology signified.

    THANKS!! :angel:
     
  7. Rik

    Rik Banned Posts: 3,814

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