80 fan blades, naturally large amount of wind can be taken away more calories per unit time. With large heat sink can be relatively easy to do a good cooling effect. But for 80 Specifications fan, the wind pressure and noise contradiction prominent, if you want to have a greater air pressure (that is, to a higher speed), the noise problem will become very serious. Mute fan would give rise to the problem of insufficient air pressure, wind less than the bottom of the heatsink with dense fin heat sink will make. So we see that most of the 80 fan radiator will be more sparse large radiator with fins.
60 fan blades small amount of wind. 60 of the fan high speed even if they will not issue too much noise, so 60 fan is easier to have a greater air pressure. Selection of excellent workmanship fan 60 coupled with dense small fins on the heat sink, often able to achieve a very high standard.
Features 70 fan is between 60 and 80 between the two, it is more moderate. But precisely because the features are not prominent, so the manufacturers are not many.
To sum up, if it is to their own computer mute the premise that the effect of heat, should be the preferred type 60 fan with a well-made heat sink.
On the shape of the blades, the number of blades, in order to achieve the purpose of quiet, of course, is preferred sickle and the number of blades as much. Many famous products is not very concerned about these areas because so much of the impact of these factors on the performance is not as bearing and speed.
The wind out of the way, I'm not optimistic about the centrifugal fan noise is the same premise, it's not as good as the air flow pressure axial flow.