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CPU fan speed not showing in BIOS or any software.

Discussion in 'General Hardware' started by Jack_Wills11, 25 Jun 2019.

  1. Jack_Wills11

    Associate

    Joined: 25 Jun 2019

    Posts: 24

    Hello everyone,
    I was hoping I could get some help with my current situation.
    I built my PC 4 years ago, but I have never been able to control/view fan speeds for the CPU or view any information about my AIO water cooler.

    My system fans are working fine with PWM control and fan curves in the BIOS, however my CPU fans are not. Furthermore, I have no control of my H100i GTX cooler in Corsair Link. I've tried contacting Corsair over the years, but they haven't been much help at all. The device is connected using the included USB to micro-USB cable, however I can see no indication of it in device manager, and nothing regarding the cooler whatsoever in CL. I have disabled "USB selective suspend" in power settings, but still nothing shows. The two cooler fans are connected to the splitter, which connects them to CPU fan header 1, however, as shown in the photo below, there is apparently no CPU fan connected. I assume the fans run at 100% all the time, as I've never seen a change in their behaviour. Turning off "smart fan mode" in MSI Click BIOS 4 seems to have no affect on the situation.

    There have been other things I've tried, but I'm struggling to remember them all right now, so I would appreciate any insight and help on the situation.

    My specifications:
    Intel core i7 4790K (not overclocked)
    Corsair H100i GTX cooler
    Corsair 16GB DDR3 Vengeance Pro (no XMP or overclock)
    MSI Z97 Gaming 5 motherboard
    MSI Nvidia Geforce GTX 970 (not overclocked)
    250GB Samsung 850 EVO SSD (programs/boot drive)
    1000GB Seagate Barracuda (games drive)
    4000GB Seagate Barracuda (mass storage drive)
    Windows 10 Pro 64bit

    [​IMG] https://imgur.com/a/fl2aASX :two images showing 'no CPU fan rpm' and 'no CPU fan detected'

    Thanks,
    Jack
     
  2. LuckyBenski

    Mobster

    Joined: 28 Dec 2017

    Posts: 4,796

    Location: London

    Your CPU looks quite toasty for BIOS TBF.

    A few questions to help fill in the gaps -

    Do the fans have 3 or 4 wires? Usually the pins go ground, +12V supply, tach (RPM signal), PWM control signal. A fan splitter usually drops the tach wire on one side as it would give false readings if it returned two fans' signals to the motherboard. Try following the third wire from the fan cable, through the splitter to the header.

    Can you rule out the header by swapping CPU and case fans around? Expect you'd see the zero RPM reading move to another header, if the issue is external to the motherboard.

    It sounds like the AIO isn't connecting via USB - again can you try a different header or even swap with something that works e.g. a front panel connector?

    What does the USB connection do? Seeing as your fans are connected straight to the motherboard so not involved with AIO control at all...

    If the fans use three wires you'll need to set the fan headers to DC Voltage control rather than PWM.
     
  3. LuckyBenski

    Mobster

    Joined: 28 Dec 2017

    Posts: 4,796

    Location: London

    N.B. if you're looking at the fan plug "head on" so straight into the pin holes, with the tab guides on top, the ground signal is the leftmost. :)
     
  4. Jack_Wills11

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    Joined: 25 Jun 2019

    Posts: 24

    @LuckyBenski

    Thanks for the response. For convenience, I have underlined the things I haven't tried/I didn't know before.

    FYI my CPU was probably quite toasty because I had the PC running for a bit beforehand, and my room gets very hot, because of the PC and my old monitor.

    I few things you've mentioned I remember trying before.

    So the fans I'm currently using are ones I bought after the cooler. I originally used the included fans, but swapped since they were too noisy. Both sets of fans displayed 0 rpm in BIOS.
    Furthermore, both sets of fans had 4-pin connectors, where the splitter converts two-4-pin into one-3-pin connector. This splitter is attached to the radiator of the cooler. I have read about this change from DC to PWM control for fans in the BIOS before, but I can't find the option in my BIOS. If you could provide any insight, that would be helpful.

    As for the USB cable, this comes directly from the pump and goes into a USB header on the motherboard. In the past I tried connecting the the cable to different headers, and tried to the front panel connector, but both showed no difference. The purpose (apparently) for the USB cable is to allow control of fan curves, pump speed, and changing the built-in RGB LED on the cooler. I don't have any of this functionality as the device is not recognised. I will try different headers/cable to see if it is visible again.

    Another thing that I hadn't heard of before was following the third wire. I understand what you mean about it returning two signals, and that's why it drops to three wires. Are you suggesting that I have put the connector on the wrong three pins of the 4-pin connector? Because that might be a reason why there is no information about the fans in BIOS/softwares.

    Thanks for your help. Hopefully you can answer my questions.
     
  5. EsaT

    Sgarrista

    Joined: 6 Jun 2008

    Posts: 8,622

    Location: Finland

    Unless your room is like 35C or more that's still toasty temperature.

    Even if splitter is only for 3 pin header lack of PWM signal wire doesn't matter for RPM monitoring.
    Assuming splitter is properly wired...

    And you can't connect standard 3 pin connector to wrong pins in standard 4 pin header, except with excessive force.
    Guide notches prevent that.
    Also having it one pin position wrong would mean fan missing that kinda necessary 12V and ground for motor to run at all.
     
  6. Jack_Wills11

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    Joined: 25 Jun 2019

    Posts: 24

    Tbh, I dunno how hot my room is. I come in here and its like an oven, unless I put the air con on. My room is also upstairs in a loft conversion so its hot up here all the time.
    I'm planning to give my PC a good clean, because with exams and revision for the last few months, it hasn't had one in a while. It's possible the dust is suffocating it quite a bit. After the clean, I'll let you know if they temperatures are better.

    As for the fan connectors, that's what I thought, because I knew there were guide notches. So that mean that all fans should be properly connected. I know that the last pin is for PWM control, so that doesn't explain the lack of RPM monitoring. What do you suggested I check for to solve the issue? @EsaT

    EDIT: I've just checked CPU temperature with Speccy and its idling at 38 to 40C. That's fairly usual I would expect.
     
  7. freddie64

    Mobster

    Joined: 22 Mar 2008

    Posts: 2,945

    Have you tried using a normal PWM fan splitter cable for the fans?

    Plug the fans with the new splitter into the CPU header and the cooler into a System header for power.

    Also, found this mentioned here https://www.corsair.com/it/en/blog/H100i_GTX_How_To.

     
  8. labcoattech

    Wise Guy

    Joined: 1 Dec 2010

    Posts: 1,068

    Location: England

    Are you able to post photos of the fan connectors and also where they are plugged in on the motherboard?

    I thought a motherboard would refuse to boot if a CPU fan wasn't detected?
     
  9. Jack_Wills11

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    Joined: 25 Jun 2019

    Posts: 24

    @labcoattech Yes sure, I can post photos of the fan connectors. I thought the exact same thing, as when I researched the issue, it said that PC's should never boot if no CPU fan is detected. So it's extremely odd that it says its disconnected in BIOS.

    @freddie64 I can see how your method would work. Since the fan splitter is directly attached to the pump block, so connecting the block to a system header and the fans to a cpu fan header may work.
    Also, I will try your optional extra step. However, surely this will just stop any control of the CPU fans altogether?
     
  10. freddie64

    Mobster

    Joined: 22 Mar 2008

    Posts: 2,945

    Added the Optional Extra Step as i thought it may be why Corsair Link is not working (motherboard PWM conflicting with Corsair Link control). This is purely speculation on my part though.
     
  11. Jack_Wills11

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    Posts: 24

    @freddie64 Yes thank you. i had managed to figure this reason out eventually. I'm planning to try this in a moment. :)
     
  12. freddie64

    Mobster

    Joined: 22 Mar 2008

    Posts: 2,945

    Hope it works for you. :)
     
  13. Jack_Wills11

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    Joined: 25 Jun 2019

    Posts: 24

  14. an0nym0us

    Wise Guy

    Joined: 15 Apr 2019

    Posts: 1,140

    Have you ascertained whether the motherboard's CPU fan header is working correctly yet? I'd suggest plugging the AIO into a system fan header, then try a known working fan in the CPU fan header to then see what the BIOS reading is like. Then you can start narrowing down where the problem is arising from.
     
  15. freddie64

    Mobster

    Joined: 22 Mar 2008

    Posts: 2,945

    Never done this myself and have never had a MSI mobo so unfamiliar with the bios, but it could be Hardware Monitor/Smart Fan Control/Disable. This may make all fans run full speed though.

    As an0nym0us suggests, plug a fan into the CPU header and see if it is working first.
     
  16. Jack_Wills11

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    Joined: 25 Jun 2019

    Posts: 24

    @freddie64 i have tried disabling smart fan mode and then checking rpm and Corsair link but it makes no difference.

    I’m about to try plugging the cpu fan pin into a system header and another fan into the cpu fan header.
     
  17. Jack_Wills11

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    Joined: 25 Jun 2019

    Posts: 24

    So replacing the CPU fan header with a system fan and the system fan header with the CPU fan pin has had successful results. In BIOS the CPU one fan has a visible rpm, meaning that there is nothing wrong with that header. However the system fan one header also has an rpm which suggests that the Corsair cooler is sending an rpm signal to the motherboard. So I’m not sure where the problem lies. I’m going to boot into windows now.

    Update: bios is now saying 0rpm for the cpu fan (Corsair cooler)

    Update 2: speedfan in windows is now saying 0rpm for the Corsair cooler.
     
  18. Jack_Wills11

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    Joined: 25 Jun 2019

    Posts: 24

    I have tried plugging the cooler into cpu_fan2 header and bios still says no rpm for cooler.
     
  19. Jack_Wills11

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    Joined: 25 Jun 2019

    Posts: 24

    So through trial and testing, I have concluded that the issue does not lie with any of the fan header; both cpu fan headers and all three system fan headers are fully functional.
    Also, every case fan, including those on the Corsair cooler, are fully functional. They receive power, have PWM control and the RPM is visible.
    The problems appear to lie with the cooler. As @LuckyBenski said, the splitter drops the tach wire on one of the fans on the splitter, however the splitter does take it from one fan as well as PWM control for both fans. This splitter goes into the pump block, and a three pin cable leaves the block. This would explain lack of PWM control, however doesn’t explain the lack of RPM monitoring. Furthermore, using the included usb header-mini usb cable or another usb-mini usb cable does not make the cooler appear under USB devices in device manager, or appear in Corsair link/iCue. This still means lack of RPM monitoring for the cooler, lack of PWM control, lack of pump speed monitoring, and lack of RGB control on the block. I am totally confuzzled.
     
  20. EsaT

    Sgarrista

    Joined: 6 Jun 2008

    Posts: 8,622

    Location: Finland

    So both fans connect to pump and then there's only one power cable from pump to motherboard?

    Would suggest getting separate splitter cable to connect fans directly to motherboard.
    Aren't many motherboards nowadays even having separate CPU fan and pump header?