Maybe this has nothing to do with computerfans, but my inline-skates also got sleeve bearings, and I use them for allmost 2 years now without 1 maintenance, so don't underestimate the quality of sleeve bearings.

uses 120mm mounting points:)

There are also material differences.

AC first used cermamic and now switched to the fluid bearings which has been Papsts standard tech for a long time, called sintec bearing. Noiseblocker has/had Ceramic bearings in the SX1 (now Coolink), but it seems that the Papst is slightly better noise/performance wise so it's possible ceramic has reached a dead end before even getting popular.

better comparison
 

From the charts it's difficult to compare the fans.

Higher speed, more cfm and more noise,
lower speed, less cfm, less noise

How to see if a fan is 'better'?
Like same noise but higher cfm?

--> plug the fan to a voltage regulator,
set at a fixed distance in the air blowing direction
of the fan a soundmeter, and regulate the voltage
so that the noise is 20db (for example)

now you only have to compare for each fan,
which fan blows harder.
--> cfm meter? i know there exist like 3spoons on
a rotator to measure the speed of the air for wheaterforecast.
but if it is just for comparison and absolute measure units
don't mather, you can hang up a piece of paper and measure
the angle the blowing fan can tilt it.

repeat this process for different sound levels,
because the wings of the fan can be designed
for slow speed and perform bad at high speed.

yes, but it's relevant what the user can really use as there are sometimes only fixed voltages

this roundup is a very good help if someone needs a 120mm fan, especially a silent one

sometimes you can measure things with the help of easier to measure things like temperature.

airflow means nothing.
you can have a fan with 50CFM that cools better then a fan with 100CFM, just because it causes the right airflow.

When the object you have to cool is in the blind spot of a fan with 100CFM or it is right in the airflow of a 50CFM fan it will make a difference.

So choosing the right fan depends from the place from more things then max CFM and noise.

For cpu cooling the low CFM fan can be better then the high CFM fan because it has allmost no blind spot. For case cooling a high CFM fan can be better because it needs to get all the hot air out the case and it doesn't matter where it will move that air to.

The best way to know what fan is best for you is to test it in the exact same conditions you want to use it. In this case the roundup tells us what fan to use as a casefan.

So choosing the right fan depends from more things then max CFM and noise. *

:D

Every-one knows how to change the voltages to 5V or 7V, instead of the normal 12V. Some motherboard offer something like speedcontroll. So even when you don't have a voltage regulator, a comparison like above (same noise --> ?cfm ) would be helpfull.

I personally think that the desing of the fans are so similar that all blindspot are alike. So a 100cfm fan will allways cool better as a 50cfm fan. Only the comparison telling the 100cmf is twice the performance of the 50cfm fan is maybe technically not good. So effective degrees of cooling are a good realworld measure.

But then the temperature of the environment, temparature of the device that must be cooled and temperature of the heatsink must all be the same when testing the different fans. When you take temperature as a measure, you must callibrate the begin situation.

And even then, you are looking at a fan-heatsink combination:
if the fins of the heatsink are close together, then this will demand a high pressure to force the air throug the heatsink.

--> http://www.matbe.com/articles/lire/2...ads/page18.php

See at the performance of the tunic tower 120mm papst fan at lower sound=speed

Like lazyman sayd, we need some technical background.

why measering airflow at same RPM sounds like fun; it's not pratical to do. I'm using the exact same hardware, only swapping the case fan, this provides info on how much air at what voltage each fan moves (lower CPU temp = more airflow).

easy to check, easy to verify.

the blind spo t has become less relevant with the mass usage of heatpipes