It's really bothering when I hear the weird noises from PC fan which is caused by CPU fan when CPU load is high. On CPU fan high rpm (e.g. while gaming) a noise from the fan installed on the side door is heard. I found the issue actually but I don't know what's the best solution to it.

When CPU fan rpm goes high an erratic vibration is transferred to the side door and the installed fan on it vibrates. I was able to determine that this weird noise is produced in cause of a little space (limitation) in which fan shaft can move freely forward. (I think this free space is because of a matter of balancing).

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As CPU fan high load, side door fan gets a horizontal movement on its shaft and noise is heard.

Is there any way to lower this space or is there a good external solution to it so that shaft won't have ability to move?

  • There exist rubber vibration isolators that you can mount between the fan and the surface the fan is mounted against. It's not a panacea, but that might help reduce vibration coupling, which should reduce the level of noise. However, if it's the fan itself that is vibrating and causing the noise, this might not provide much of an improvement. I don't see it hurting, though, so it might be worth a try. – user Jul 13 '15 at 12:21
  • So replace the fan. The fan I assume isn't new, and when it was new, did not always make this sound. If it is new, and it always made this found, then its likely a mechanical defect. – Ramhound Jul 13 '15 at 12:25
  • Personally, I recommend a new fan, and perhaps turn up the volume a little if necessary. If your PC is really hot enough to need the cooling, then it is better to deal with teh noise, unless it is indicative of a failure in the fan. Never choose quite over cool, because you will likely never choose not to play a game even though it might damage your hardware. – Frank Thomas Jul 13 '15 at 12:30
  • @Ramhound Fan doesn't produce noise at normal usage. It's the shakes that are transformed from CPU fan to side door then case fan. So I don't think it is the fan itself that is the culprit? I just want to fill the movable part if that doesn't make trouble. – rev Jul 13 '15 at 13:19

Two things:

1- replace the fan and see if that works.

2- as an extra measure, or in case step one fails, install dynamat or another sound deadener on the inside of the PC case where the fan is attached to. The reason for doing this is based on the idea of natural frequencies. It could be the fan oscillates at the perfect frequency which causes the PC side to produce a noise. By adding sound deadneding material, this can be prevented.

Link to learn more about natural frequency: http://www.physicsclassroom.com/class/sound/Lesson-4/Natural-Frequency

  • Thanks. I didn't find anything related about dynamat on the case of me. Would you give some example product link? – rev Jul 13 '15 at 13:23
  • Amazon has if for around 12 dollars. amazon.com/gp/aw/d/B00020CATC/… – Geruta Jul 13 '15 at 13:27

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