I have been experimenting with air coolers on my CPUs, and in particular with fans. Some fans are noisy, and get noisier with age. While I regularly clean the block, the fan blades as well as blow away any dust buildup, the air flow still sounds very turbulent. After about the 8 year point nothing will help other than to swap out the fan. What is the actual root cause of increased turbulent flow (which is what I believe I am listening to)?
Dust on the fan blades cause micro disturbances that sum up to a higher noise level.
Cheap models have a plain bearing that wears out, causing a kind of grinding noise.
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It's definitely not a grinding noise.
Fan blades are regularly kept clean with wet wipes, and after compressed air has cleaned the machine as a whole.
Replacing thermal paste on a 6-month cycle has a marginal effect, but this is BIOS software driven, not mechanical.
what make/model of fan , motherboard/casing ... all can contribute to 'noise' is it a recent phenomenon ?
have you measured the level (decibels) ....
is the host being worked to death by processing .....
any other hosts with same/similar configs that are not experiencing same ?
The question is more generic in nature, namely the root cause of turbulent flow on a CPU block, all else being equal (ie: the machine is regularly being freed from dust), given that this always happens regardless of model. And yes, about two-thirds of all machines are either 24/7 calculating or they're off. Limiting the load barely helps, there is still this incessant rushing of air and I can tell from the noise level which machine has the oldest CPU fan.
Also tried bicycle chain oil for in the bearings, but also that has a marginal effect. More and more components are passively cooled, so I don't actually have the problem in principle.
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Not knowing the complete architecture and apps....
Cheap fans are common and these cheap fans degrade quickly.
Would be better to post the exact fan model numbers, etc
Maybe it's important for you to determine if:
- Is it indeed turbulent flow you're listening to, and not other fan ageing side effects, like dusty or rusty bearings or worn-out blades or else?
- If it is, is it indeed mechanically caused (some actual air flow restriction or worsened path), or could it be, say, higher fan speeds due to age-related lowered efficiency?
- Could your procedure for cooler replacement end up doing any cleanup, realignment or wherever refresher, which doesn't happen in your block cleaning recipe?
Just my 2 cent
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That seems to suggest that the noise is also generated in the hub and bearings, which is indeed not unlikely.
Most of the older fans are out of HP servers and Dell servers The newer (and quieter) ones are Corsair or CoolerMaster. What the newer ones have in common is that they're larger: 8cm and up.
Likely so, age is definitively a factor, but I just realised that the smaller fans are more prone to degradation and causing turbulence than larger ones. More testing needed.
Idem.
Exactly, that is also my question. Some ancillary cleanups seem to help a little bit, others not at all, but none make a noticeable difference. This means that in my setup I will be less likely to clean the fan separately and be bold in swapping them out for larger ones or passive ones.
Ah, so fans not only differ in age, but also in make/model! This surely makes a broad difference.
On fan sizes: bigger ones can yield the same air flux with less air speed. That, definitely, brings in less turbulence, than less noise.
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