SPCR

If you wish to discuss this news... Coding Horror's Quiet PC Guide

Ok....I have at least one concern with this article. When the author says "And remember, kids, always stop fans by touching them in the center, not in those whirling blades!", IMHO he is making a mistake.

You may save a cut finger stopping the fan this way, but you may cause permanent damage to the fan bearing. The amount of relative pressure required to stop a fan, applied directly to the shaft center(the bearing area), is much greater than these small bearings were ever designed to encounter.
It would be easier on the fan to put a straw or something between the fan blades with the computer off. Then start the computer, listen to the noise, remove the straw (the fan starts turning), and guage the change in the sound.

This is much easier on the fan, and your fingers as well. These computer fans can sustain damage easily if handled improperly. My 2c......

Other than that though, it's a very good "Silencing 101"-type article; maybe we should pinch it and use it on SPCR as a guide for newbie's?

I do not agree on point #2. If a certain CFM is needed to cool the system, it will almost always be more silent with two slow fans instead of one fast.

haugland wrote:I do not agree on point #2. If a certain CFM is needed to cool the system, it will almost always be more silent with two slow fans instead of one fast.

Or one larger slow fan instead of one fast fan.

Case fans typically use a very simple thrust bearing at the end of the fan shaft, which is either truncated-conical or spherical in shape. The use of the simple bearing is fine for this since fan impellers never really encounter an axial pressure during their operation, and the friction surfaces are rarely engaged. It is true that a radial bearing is not meant to bear thrust loads, but the fan manufacturers have typically thought this one out by the inclusion of the simple thrust bearing at the end of the shaft. Sunon's Vapo bearing technology actually relies more heavily on this thrust bearing at the end of the fan's shaft, since it is this bearing that works against the axial force applied by the magnetic plate.

Bottom line -- I don't really think the thrust load created at the hub by stopping a fan impeller will hurt a fan or decrease the life of its bearings.