"Tiny Cooling Fan" side length of 12cm, about 1200rpm speed you can get a good amount of wind and low noise, although the wind speed is less than this amount is acceptable, but the pressure is weak, but fortunately more for liquid-cooled radiator, etc. Duct heat sink for cooling the computer switching power supply design for air flow made certain requirements; further increase the speed to about 1500rpm, you can get a large amount of wind noise is still acceptable; speed exceeds 2000rpm, you can get a substantial amount of wind , pressure is acceptable, due to the larger blades, which are not Min conditions, the noise will increase dramatically. "Tiny Cooling Fan" 9cm (side length 92mm) axial fan blades to increase the size of the area and too much wind, but 8cm lower fan noise in the same amount of wind than the relatively 8cm, subject to a small range of ages, but did not common. Another common cooling fan - 8cm outlet side of the turbo fan: "Tiny Cooling Fan" about 1500rpm speed you can get a good amount of wind and low noise, below this speed may be affected due to insufficient air flow cooling effect ; further increase the speed to about 2500rpm, get a good amount of wind, and the greater pressure, noise barely acceptable; speed exceeds 3500rpm can be included in the "violent" fan of the column, due to the special design of the structure, the noise has been with 8cm Axial "violence" fan par challenge endurance limit of the human ear.