In earlier times I did a lot with quiet/silent computing mods. At a very high level
@Fritz is correct, but I can't let this go by without some comments.
My experience with trying to tame the Noise Beast.
1. The amount of air a given fan move is related to how loud it is. The louder, the more air it moves. And conversely, the quieter the fan the less air it moves.
Partly true. Noise isn't related to moving air - its related to air hitting things and vibrating. Or things that move the air vibrating while they do it, like Fans.
At similar size and airflow you can get higher quality fans that move the same amount of air with less noise. But the marketplace is fickle and you really only find the sizes and speeds that have enough of a market to make selling them worthwhile. So your choices and how much you can achieve is limited. If you need to move the same amount of air as a 40,000RPM 80mm fan you can, indeed, make it quieter. But you can't make it quiet. If you are working with 1U (40mm fans) then just give up...
Also, while the better fans (Noctua, etc) do have improvements in bearing quality and blade shape most of their benefit comes simply from slowing the fan down - thus reducing the airflow. In most cases you can achieve 80-90% of the same benefit by just slowing down the fans you have (either with a resistor mod or PWM control).
2. The amount of air that moves through the box determines how cool your CPU, HD's, Ram and video card run.
Yup - nothing but truth there.
3. You should always make cooling mods in the heat of the summer, not when in winter. If you live in Nome Alaska or Siberia, this may not apply.
Generally true, but YMMV depending on your environment.
Fan mods never worked to my satisfaction. They always resulted in overly high temps all the way across the board during the summer. I finally settled for moved the air through the server room as much as possible via improvised box fans and a couple of table fans aimed at the rack. Even then, in the heat of the summer (South Georgia), the server room is still a good 10 degrees warmer than the rest of the house when they're all running.
This is especially true when working with small fans (40mm). The quiet fans just don't move any meaningful amount of air at all. With larger fans (120mm) the quiet fans really do work well in most conditions.
In my experience, you can do more good by making sure the air moves through the case and over the equipment correctly. Seal off places you don't need/want the air to go into (or come from). Build ducts and shrouds to make sure the air from the fans hits the heatsinks. Lost of air moving randomly does not cool your equipment.
Bottom line is - Too keep them cool, you gotta move air, lots of air.
Yup - pretty much this.
