Question AIO Radiator Fans (CPU_FAN) are stuck at a constant 1500 RPM ?

[snoopix]

Hi there,

So, I have a TH420 ThermalTake AIO Cooler placed on the front of my case. And I have had the build for 4 months now but never really took into consideration on how loud my AIO fans are.

I am using a Asus Prime B650 Motherboard. Went into BIOS to check the speed of the fans and see If I can lower them, however, even If I change the curve on Qfan, the fan is still stuck on 1480-1500RPM.

I also installed Armoury Crate to check, and saw that my CPU fans has a stuck range of 1450-1500RPM on whatever % I put on the curve.

So I checked in the motherboard to see if I have my connection right. And yes I do, my AIO Pump is connected to the aio_fan and the fans are connected to the CPU_FAN connector. I also checked if the CPU_FAN is a 4-pin connector which allows rpm control, and in this specific motherboard yes it is.

Anyone had this issue and knows any fix? Thanks in advance

 

[Paperdoc]

I presume in your post you meant to say that the PUMP is plugged into the AIO_PUMP header. Right?

So here's how the headers should be set in BIOS Setup. See the BIOS manual here

https://dlcdnets.asus.com/pub/ASUS/mb/13MANUAL/PRIME_PROART_TUF_GAMING_AMD_AM5_Series_BIOS_EM_WEB_EN.pdf?model=PRIME B650-PLUS

See p. 10 for the QFAN screen. Select the header to adjust at the left.

At upper right set AIO_PUMP to PWM Mode, not Auto
At the bottom, set its profile to FULL SPEED

Now select the CPU_FAN header, and set
At upper right set CPU_FAN to PWM Mode, not Auto
At the bottom, set its profile to STANDARD

When done, back out using Esc to Main Menu, then F10 to reach the Exit Menu (p. 92). There choose Save Changes & Reset to reboot.

Recognize that CPU_FAN will show you the speed of ONE of the rad fans - it cannot "see" all three. AIO_PUMP may tell you is is showing you a FAN speed, but really it is your PUMP if you have plugged in in there.

This should make your pump run full speed all the time as it is designed to do. The specs on this say it should run about 3200 RPM. If the pump is set wrong so it runs more slowly, circulation of fluid to carry heat to the rad is impeded and the fans have to run too fast to compensate. The rad fans will vary their speeds automatically according to the temperature sensor inside the CPU chip. Fan max speed is spec'd at 1800 RPM.

If you are using Armory Crate, make SURE it is set the SAME way as above. It is a utility that makes things easy to see and adjust while actually operating in Windows. But the How of this is important. It simply takes over control settings for your fans by imposing its settings in place of what you have set in BIOS Setup. So if Armory Crate is set wrong, that is what the fans will do.

 

[snoopix]

I presume in your post you meant to say that the PUMP is plugged into the AIO_PUMP header. Right?

So here's how the headers should be set in BIOS Setup. See the BIOS manual here

https://dlcdnets.asus.com/pub/ASUS/mb/13MANUAL/PRIME_PROART_TUF_GAMING_AMD_AM5_Series_BIOS_EM_WEB_EN.pdf?model=PRIME B650-PLUS

See p. 10 for the QFAN screen. Select the header to adjust at the left.

At upper right set AIO_PUMP to PWM Mode, not Auto
At the bottom, set its profile to FULL SPEED

Now select the CPU_FAN header, and set
At upper right set CPU_FAN to PWM Mode, not Auto
At the bottom, set its profile to STANDARD

When done, back out using Esc to Main Menu, then F10 to reach the Exit Menu (p. 92). There choose Save Changes & Reset to reboot.

Recognize that CPU_FAN will show you the speed of ONE of the rad fans - it cannot "see" all three. AIO_PUMP may tell you is is showing you a FAN speed, but really it is your PUMP if you have plugged in in there.

This should make your pump run full speed all the time as it is designed to do. The specs on this say it should run about 3200 RPM. If the pump is set wrong so it runs more slowly, circulation of fluid to carry heat to the rad is impeded and the fans have to run too fast to compensate. The rad fans will vary their speeds automatically according to the temperature sensor inside the CPU chip. Fan max speed is spec'd at 1800 RPM.

If you are using Armory Crate, make SURE it is set the SAME way as above. It is a utility that makes things easy to see and adjust while actually operating in Windows. But the How of this is important. It simply takes over control settings for your fans by imposing its settings in place of what you have set in BIOS Setup. So if Armory Crate is set wrong, that is what the fans will do.

Hey man, thanks for the reply!

Yes I did mean the AIO_PUMP

Also, I have set all my settings as you've suggested as well on my BIOS and still, my CPU_FAN (aio fans) are running at 1488RPM even tho the cpu temp is like 35C degrees. Here are the pics of the bios:

https://drive.google.com/file/d/1htyjTLcNJ3wQoF1QCW4_Kaeg744mR2A7/view?usp=drive_link, https://drive.google.com/file/d/18oAhTMtGg5gJeAZO1Bbyg3mF0miRbI6H/view?usp=drive_link, https://drive.google.com/file/d/1pCrfo-F9qoaxWDLAMlDcwolhnDZh0Oy1/view?usp=drive_link

 

[Paperdoc]

That photo shows a speed on CPU_OPT. What is plugged in there?

 

[snoopix]

That photo shows a speed on CPU_OPT. What is plugged in there?

I did have one of my chassis fans pluuged in it. Howver, I managed to fix the issue now and also changed the header of that fan.

So basically, looks like my aio_pump headers had was blocking my rpm for the cpu_fan header as well.

I changed my aio fans header from cpu_fan to a chassis_fan header and now I am able to control the speed and now they are sitting at 1000rpm which makes a ton of difference on noise now.

Also now I can control that case fan that was plugged in cpu_opt which was uncontrolable as well.

For anyone trying this, when you get the "CPU NOT DETECTED" error when booting, just go into bios and set it to ignore it.

Cheers!