Question Leaving CPU fan header unused - is this okay?

awong918

Prominent
Jul 14, 2018
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I think the cpu fan header on my B450i Strix is defective. Any fan plugged into it will oscillate in speed, creating a very annoying oscillating humming sound with my ML120. Is it ok to not use it? Only issue it's causing so far is a "cpu fan error" message that pops up when starting up my computer (which I can bypass by just going into and exiting the bios). Will it cause any other issues?

I'd rather not go through the trouble of RMA'ing if it's not needed.
 
I think the cpu fan header on my B450i Strix is defective. Any fan plugged into it will oscillate in speed, creating a very annoying oscillating humming sound with my ML120. Is it ok to not use it? Only issue it's causing so far is a "cpu fan error" message that pops up when starting up my computer (which I can bypass by just going into and exiting the bios). Will it cause any other issues?

I'd rather not go through the trouble of RMA'ing if it's not needed.
Have you tried setting the fan header to DC mode and running it at full voltage... or alternatively setting it to PWM mode and at 100% ?

So long as you connect the CPU fan to something so it provides processor cooling I don't think it will matter beyond that message. You could possibly even avoid the message by removing the RPM sense wire from the fan plug and connecting it to the RPM sense pin on the CPU fan header. That will fool it into thinking a fan is connected there when it's actually connected elsewhere, and then all CPU fan speed indicators will also read the fan speed.

BTW... the preferred operation of an AIO liquid cooler is to connect the water block pump to the CPU 'fan' header and it SHOULD be run at full speed, DC mode, all the time. The radiator fan(s) should be connected to any available chassis fan header.
 
Last edited:

awong918

Prominent
Jul 14, 2018
20
0
510
0
Have you tried setting the fan header to DC mode and running it at full voltage... or alternatively setting it to PWM mode and at 100% ?

So long as you connect the CPU fan to something so it provides processor cooling I don't think it will matter beyond that message. You could possibly even avoid the message by removing the RPM sense wire from the fan plug and connecting it to the RPM sense pin on the CPU fan header. That will fool it into thinking a fan is connected there when it's actually connected elsewhere, and then all CPU fan speed indicators will also read the fan speed.

BTW... the preferred operation of an AIO liquid cooler is to connect the water block pump to the CPU 'fan' header and it SHOULD be run at full speed, DC mode, all the time. The radiator fan(s) should be connected to any available chassis fan header.
thanks for the quick reply!
I've done the latter (100% pwm mode), think it worked fine. I prefer a quiet system, however, which is why I prefer not to run it at 100% (and prefer to connect the aio pump to the pump header, as any fan connected to it will run at full speed and be really noisy)
 
thanks for the quick reply!
I've done the latter (100% pwm mode), think it worked fine. I prefer a quiet system, however, which is why I prefer not to run it at 100% (and prefer to connect the aio pump to the pump header, as any fan connected to it will run at full speed and be really noisy)
At least your mobo has a pump header so that's good.

Then just move the fan to another header if that one won't provide a steady output at less than 100%. All you'll get is the message, and you could probably trick it by putting the fan's RPM sense wire on the sense pin of the CPU header and not get the message at all.
 

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