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  1. #1
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    Prime Z690-P CPU Fan speed not working correctly

    I have a Prime Z690-P and all setup working perfectly with Windows 11, but noticed an oddity with the CPU Fan. I'm using a CoolerMaster EVO V2 but the same happened with the Intel stock cooler.

    Basically the speed goes in reverse, by that I mean as the CPU temperature increases, the fan speed of the CPU cooler slows down and hits the minimum setting, as the CPU cools down, the fan speeds up. If you think about a dot on the Q-FAN chart for the temperature, it moves in the wrong direction. All other fans work correctly. Also when in the BIOS and in the Q-FAN settings, if I adjust the chart the fan works normally, for example set turbo mode, the fan speeds up, select quiet mode the fan slows down. It just seems that the temperature change moves the speed in the opposite direction that it should. I've tried DC Mode and PWM Mode, in DC Mode I set the fan to stop at it's lowest setting, and sure enough, run a benchmark to stress the CPU the fan slow downs and stops, stop the benchmark and see the CPU temperature fall, the fan starts back up again! I've ran several Q-Fan calibration tests and it's made no difference, the CPU fan always behaves in the opposite manner it should with temperature. Obviously this isn't good! I've done a full reset of the BIOS and it made no difference.

    I downloaded some fan control software to run in Windows and configured it for the CPU fan, and this works it perfectly, and so points the finger at a bug in Q-FAN firmware/BIOS.

    Posting here in the hope it gets picked up by Asus, or if anyone has any ideas how I might fix it as I'd rather not run software to control the fan.

  2. #2
    ROG Enthusiast Array DragDay7 PC Specs
    DragDay7 PC Specs
    MotherboardAsus Z690-A PRIME DDR5
    ProcessorIntel i7-12700KF
    Memory (part number)Corsair 2x16GB 5600MHz CL36
    Graphics Card #1MSI 2080 Trio X
    MonitorHuawei MateView GT 34, Acer V247Y
    Storage #1Plextor PX-1TM10PGN
    CPU CoolerCustom EK Water Cooling
    CaseCorsair 5000D
    Power SupplyCorsair RM 750
    Keyboard SteelSeries APEX 7
    Mouse Logitech G403
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    What's your bios version?

    Also your cooler has PWM fan and you should leave its mode like that.

  3. #3
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    Quote Originally Posted by DragDay7 View Post
    What's your bios version?

    Also your cooler has PWM fan and you should leave its mode like that.
    BIOS Version is 1401. I switched to DC mode just to troubleshoot in case it was some odd issue with the fan responding to PWM but it behaved the same, indicating the DC voltage was being reduced with increases in temperature, the opposite of how it should work. It's back on PWM after trying DC mode out.

    The same fan type is being used as an exhaust fan and that works as expected, as does the two front fans, it is just the CPU that is working backwards. Any fan connected to the CPU-FAN header is doing the opposite of what it should with temperature.

  4. #4
    ROG Enthusiast Array DragDay7 PC Specs
    DragDay7 PC Specs
    MotherboardAsus Z690-A PRIME DDR5
    ProcessorIntel i7-12700KF
    Memory (part number)Corsair 2x16GB 5600MHz CL36
    Graphics Card #1MSI 2080 Trio X
    MonitorHuawei MateView GT 34, Acer V247Y
    Storage #1Plextor PX-1TM10PGN
    CPU CoolerCustom EK Water Cooling
    CaseCorsair 5000D
    Power SupplyCorsair RM 750
    Keyboard SteelSeries APEX 7
    Mouse Logitech G403
    Headset Shure SRH 440
    Mouse Pad DreamMachines
    OS Windows 11
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    Does bios fan monitor shows rpm correctly or it's reversed too?

    I thought maybe PWM signal is inverted but since in DC mode it behaves the same way, also any software controls fan just fine that's not the case. Can you check in hwinfo if any temp sensor shows reversed value?

    Your board has some unique feature there xD

  5. #5
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    The BIOS and anything else that monitors/shows the RPM is showing the correct speed of the CPU fan, and I can visually confirm this, a fast fan shows high RPM and vice versa.

    No negative temperatures shown anywhere. Here are some examples:

    First is HWMonitor showing fans when the CPU is under load and at a high temperature using software to control the CPU fan, this software is told to monitor the CPU package temperature and speed up with higher temperatures, as expected the CPU fan ramps up very quickly when I run a stress test. So this works, showing the hardware is all okay.

    Click image for larger version. 

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    Now under BIOS control, system at rest as seen by the temperatures, CPU fan running at a low speed (although not at the lowest speed that is set in Q-FAN which is around 650rpm, so Q-FAN is running the fan faster than expected for this temperature), note that Chassis Fan 1 is the rear fan inline with the CPU cooler, this is set to off in Q-FAN when CPU is below 35 degrees as no need for it to help expel hot air from the CPU which is little more than room temperature when at rest, and I like the quiet.

    Click image for larger version. 

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    So now start a bench test and raise the CPU temperature, expected result is the CPU fan ramps up, it should be >1700 RPM when at 65 degrees or more, as set in Q-FAN.

    We can see the stress test running in the graphic below by high CPU temperature, but the CPU fan speed has now reduced to the lowest setting it can go in Q-FAN, obviously this isn't correct. The rear exhaust fan has correctly ramped up to help move hot air out the back, so it knows the CPU is hot and works as expected. When the stress test stops and temperatures drop again a few seconds later, the CPU fan speed increases back up from it's minimum speed to around 740 RPM again, so doing the exact opposite of what it should do.

    Click image for larger version. 

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    Note this replaces another ASUS motherboard based PC I've been using for many years with Q-FAN and that always worked fine, and I'm not new to Q-FAN.

    This has to be a bug in the ASUS Bios and for CPU fans they've got a formula error.
    Last edited by plee5509; 06-14-2022 at 11:18 AM.

  6. #6
    ROG Enthusiast Array DragDay7 PC Specs
    DragDay7 PC Specs
    MotherboardAsus Z690-A PRIME DDR5
    ProcessorIntel i7-12700KF
    Memory (part number)Corsair 2x16GB 5600MHz CL36
    Graphics Card #1MSI 2080 Trio X
    MonitorHuawei MateView GT 34, Acer V247Y
    Storage #1Plextor PX-1TM10PGN
    CPU CoolerCustom EK Water Cooling
    CaseCorsair 5000D
    Power SupplyCorsair RM 750
    Keyboard SteelSeries APEX 7
    Mouse Logitech G403
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    OS Windows 11
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    Quote Originally Posted by plee5509 View Post
    This has to be a bug in the ASUS Bios and for CPU fans they've got a formula error.
    I'm not that sure, if that'd be the case you wouldn't be the only one with that issue.

    Have you tried clearing CMOS by unplugging power cord and shorting CLRTC pins? They're at the bottom of your motherboard.

    Other than that and reflashing bios I have no idea and you should wait for someone smarter. Hell, even if I try to google your issue there is none.

  7. #7
    ROG Guru: Green Belt Array ahfoo's Avatar
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    Hi mate, maybe you want to try the new beta bios to see if it solved your problems.

    https://dlcdnets.asus.com/pub/ASUS/m...-ASUS-1601.zip

    Please return to BIOS default if you want to upgrade to this version. If I were you, I will reset the original bios setting before updating to this version. After updating the bios. Reset to default again. I am not sure others, but that my habit for years. Most of them will think I over zealous but that what I do and never go wrong for the past years.
    Last edited by ahfoo; 06-14-2022 at 12:32 PM.

  8. #8
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    Quote Originally Posted by DragDay7 View Post
    I'm not that sure, if that'd be the case you wouldn't be the only one with that issue.

    Have you tried clearing CMOS by unplugging power cord and shorting CLRTC pins? They're at the bottom of your motherboard.

    Other than that and reflashing bios I have no idea and you should wait for someone smarter. Hell, even if I try to google your issue there is none.
    Yes tried clearing the CMOS and BIOS has been re-flashed. Maybe others are having the issue, they just don't realise they are, initially I had no idea I had this behaviour going on as all the fans were all ramping up with the CPU by default so if the CPU fan was slowing down you wouldn't have known it, it was only when I was taming things and monitoring temperatures that I realised this was happening. Also if using the Asus software to control the fans it might well be that takes over from the BIOS and so it works okay. I'm certainly not installing that Asus software just to find if that is the case, it's terrible and I had to reinstall Windows 11 after an initial play about with it to get rid of it!

  9. #9
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    Quote Originally Posted by ahfoo View Post
    Hi mate, maybe you want to try the new beta bios to see if it solved your problems.

    https://dlcdnets.asus.com/pub/ASUS/m...-ASUS-1601.zip

    Please return to BIOS default if you want to upgrade to this version. If I were you, I will reset the original bios setting before updating to this version. After updating the bios. Reset to default again. I am not sure others, but that my habit for years. Most of them will think I over zealous but that what I do and never go wrong for the past years.
    I will give it a go, I did look at that and nothing in the release notes say Q-FAN fixes so I'm guessing it will be the same, but will try later and report back.

  10. #10
    ROG Guru: Green Belt Array ahfoo's Avatar
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    Quote Originally Posted by plee5509 View Post
    Yes tried clearing the CMOS and BIOS has been re-flashed. Maybe others are having the issue, they just don't realise they are, initially I had no idea I had this behaviour going on as all the fans were all ramping up with the CPU by default so if the CPU fan was slowing down you wouldn't have known it, it was only when I was taming things and monitoring temperatures that I realised this was happening. Also if using the Asus software to control the fans it might well be that takes over from the BIOS and so it works okay. I'm certainly not installing that Asus software just to find if that is the case, it's terrible and I had to reinstall Windows 11 after an initial play about with it to get rid of it!
    If you made full use of bios QFAN curve, you dont need to install asus or third party fans control.

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