P8Z68 Pro Fan Speed

Discussion in 'Motherboards' started by Morias, Oct 20, 2011.

  1. Morias

    Morias Junior Member

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    Hey all,

    Just built a new PC, and as it's been a while since I last did it I'm sure that there's a silly answer to this one.

    My problem is I don't have any control over the CPU_Fan on my P8Z68 Pro - it's running at 2000 rpm no matter what I do. I'm running a Corsair A70, and have both fans plugged into the CPU_Fan header via a 3 pin splitter.

    So far the following has had no effect:
    Changing the CPU_Fan profile in BIOS
    Changing the CPU_Fan profile in AI suite
    Using a User profile in AI suite
    Using Speedfan

    The mobo is running on v 0501 - I believe the most recent is 0606, is flashing the BIOS what I need to do? Was leaving this as last option as to be honest it scares me!

    Thanks in advance for any help.
     
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  3. Diogenes2

    Diogenes2 Platinum Member

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    The three pin splitter is the problem..

    I believe you need four wires to control the speed from the mobo, Otherwise you need some type of add-on speed control ..
     
  4. Morias

    Morias Junior Member

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    Hmm, I was under the impression that both 3 and 4 pin control was possible.

    4 pin (PWM) control is via regulating the duty cycle of the van.

    3 pin control is achieved through voltage regulation.

    Is this not correct?
     
  5. Diogenes2

    Diogenes2 Platinum Member

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    You can adjust 3 pin with voltage regulation, but I believe you have to run add-on software ( or hardware ) to control it.

    I don't believe it will do it automatically through the BIOS .

    there is a fan control in the Asus AI Suite ..
     
    #4 Diogenes2, Oct 20, 2011
    Last edited: Oct 20, 2011
  6. Morias

    Morias Junior Member

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    I have attempted to use AI Suite, as well as an external program (Speedfan) - neither have had any effect on the CPU fan speeds.
     
  7. coffeejunkee

    coffeejunkee Golden Member

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    Current Asus motherboards can only control 4-pin pwm fans connected to the cpu fan header. My old P5B board could control both 3 and 4-pin fans, but somewhere down the line this feature was scrapped.

    You could either buy new pwm fans for the A70 or a new cooler that comes with pwm fans, like CM 212+, Scythe Mugen 2 or Thermalright Macho/Archon.
     
  8. lehtv

    lehtv Elite Member

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    My current P6TSE can control the speed of fans connected to the 3-pin chassis fan headers. I haven't tried a 3-pin fan on the CPU header. I would venture the guess that the new boards can still control the 3-pin fans attached to chassis fan headers, but for controlling CPU fan speed you need a 4-pin fan. Perhaps Asus thinks it's not necessary to enable voltage control on the CPU fan header when it supports PWM control which is superior to voltage control.

    OP, you could try attaching your CPU fan to one of the chassis fan headers and see if you can control the chassis fan speed in BIOS.
     
  9. Morias

    Morias Junior Member

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    I've ordered a couple of 120mm Akasa Apache Ultra Silent Fans which have PWM control, just going to replace the fans on the A70 with these so problem solved.

    I do feel it's too early for 3 pin voltage control to have died, as even though PWM is the future, it's takeup is not there yet.
     
  10. dbrons

    dbrons Member

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    Good choice :) And keep in mind you have two seperate PWM headers on your board.

    Dave
     
  11. coffeejunkee

    coffeejunkee Golden Member

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    So do I, still plenty of good coolers out there that come with 3-pin fans, like Noctua D14 for example. Also, I wish mobo manufacturers were more clear in their communication of what headers can be controlled using which fans. Most reviews tend to miss out on stuff like that.
     
    #11 coffeejunkee, Oct 23, 2011
    Last edited: Oct 23, 2011
  12. Morias

    Morias Junior Member

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    Installed the two Akasa fans and woop! Glorious silence :) Cooling performance is slightly worse than the original fans, but only by a degree or two at load.

    Agree about the lack of information on fan headers from manufacturers. For completeness, here's what I found out about the P8Z68-V Pro Fan Headers:

    CPU_FAN - 4-pin, PWM control only
    CPU_FAN_OPT - 4-pin, PWM control, linked to CPU_FAN duty cycle
    CHA_FAN1 - 4-pin, voltage regulation only (Might be wrong on this, but I don't believe from what I've read that the +5v pin on this header actually acts like PWM)
    CHA_FAN2 - 3-pin, voltage regulation, linked to CHA_FAN1 voltage
    PWR_FAN1 - 3-pin, no regulation
    PWR_FAN2 - 3-pin, no regulation
     
  13. BonzaiDuck

    BonzaiDuck Lifer

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    This is very interesting. What was the source? It seems consistent with my own observations -- focused on erratic behaviors for putting a 0.7A/12V fan on CHA_FAN2 when a 0.4A/12V fan was already operating under QFAN as ideally expected.

    For earlier-gen ASUS motherboards, the printed manual had always been specific about "total" amperage limits across all the fan-plugs, or the average amperage limit per plug. Since the P8Z68-V-Pro manual shows no such indication, did you discover any specific information about the amperage limits as well?
     
  14. Morias

    Morias Junior Member

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    No single source, it was gathered from various posts/reviews.

    Nothing official on the amp limits, though plenty of anecdotes putting it at 1A on every header. The manual does state that CPU_FAN has a 1A limit.
     
  15. BonzaiDuck

    BonzaiDuck Lifer

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    Sorry for the delayed response. Yes, that's true about the CPU_FAN limit (in context of the design where there is both a CPU_FAN and OPT_CPU_FAN. It had seemed observable and obvious from experiences with earlier-gen motherboards that both the per-fan-plug limit and the overall total amperage was important.

    That gets back to our observation that somehow, the CHA_FAN2 plug is somehow linked to the CHA_FAN1 usage.

    My own fan-deployment is "tentative." There are two 200mm intake fans using different amperage (the NZXT uses 0.7A), an NMB-MAT (Panaflo) exhaust fan 120x38mm with 0.40A, and the two Noctua fans that came with my NH-D14 cooler (both at about 0.10A each and connected to the two CPU fan plugs.

    My goal is to eliminate both the weight and power draw from the two Noctua fans. I think I could replace all the Panaflo and Noctua fans with a Delta Tri-Blade 120x38mm 12V @ 0.80A deployed as rear-exhaust, by enclosing the NH-D14 with a foam-board or Lexan duct. The Delta is very quiet at speeds below 2,000 rpm, so if the thermally-adaptive speed for either CHA-FAN1 or the (main) CPU_FAN work properly, it would work as desired.

    System is cool and quiet as it is, so I contemplate these changes carefully and patiently with no hurry. Ideally, if I can thermally control both the NZXT intake and either the Delta by itself or a combination of the Delta and Panaflo, it would be quieter at regular operating speeds, and the fans would spin up when the processor is under load. And I don't imagine that the full fan speeds would be reached under the sorts of gaming usage I've had with this system.

    I still can't understand why ASUS cannot print a single small paragraph addition to their manual that gives the individual and total specs for the fan plugs on these motherboards.
     
  16. Methodical2

    Methodical2 Junior Member

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    Definitely bad or lack of detailed data in Asus' manual. I told the tech folks this, too. I agree with this statement as I was in the same situation when I built my system over the Thanksgiving holiday, except the 212 came with a 4 pin fan, but the case fans were all 3 pins. I called Asus and was told the exact same thing as below.

    Al