I find manufacturer specifications on dBA rating are mostly out of line in real world. Based on what I’ve seen and experienced, a quiet room is about 35 to 40 dBA during day time and a very quiet room may be down to 30 dBA which is rare in today’s society with so much noise pollution. Ratings of most fans are below 35 dBA which means you would hardly hear them run. It is NOT the case here.
The size of the fan increase does not mean reduction of noise when rotation speed is the same as the smaller counterparts. However, large size fan could replace two smaller size fans and have the same effect on air movement, which in some cases do reduce noise level.
Water cooling does not provide any less noise pollution; in fact, it increases noise level because if a single 120 mm is not enough one could get a radiator that will house three of them.
The noise level generally will increase when the fans are mounted on heatsink and radiator from the effect of wind resistance and turbulence. Conclusion:
"The Tree sounds when the Wind blows" is a valid statement. I find the options to reduce noise level from PC using active cooling water-cool or heatsink are:
1) Reduce the number fans used whenever possible.
2) Use sound insulation materials
3) Use larger fan only if it replaces two smaller ones.
4) Use low RPM fans whenever possible.
5) Stay away from buying high heat loss processors.
As I "mild" overclocker, I would have to cut my loss on the Prescott. As a consumer, When I read the specification stating an 80 mm fan with 3,000 RPM and 28 dBA or a 120 mm at 2,500 RPM with 32 dBA then I know the reading must be taken many feet or meters away. More about building a silent PC here
This article is not to inflame anyone with my opinion based on the findings. It is merely an exercise in refreshing the little knowledge I have had learnt more than 15 years ago. Please feel free to make your comments forum thread