Apparently the bearings of the old 40x40x20 fan in my recently bought e6400 are worn out.
The noise is very irritating, but the replacement I had in stock, didn't help much either.
Probably too many rpms and/or way more cooling power, or whatever.
So now I plan to replace it with a new low noise Sharkoon fan (type S40).
My challenge however is that it has a displacement of only 5.9 ccm/hour, while the old one pushed away 8.8 ccm/hour.
Would that be too big of a difference in heat accumulation, you think?