The main performance of the fan is shown in the following aspects: speed, blade shape, blade Angle and bearing system.  Under normal conditions, the fan speed is indicated on the radiator specification book.  Generally speaking, 30% of the heat dissipation effect of the radiator depends on the speed of the fan.  But the higher the fan speed, the better.  Right fan speed resolution should be based on the calorific value of CPU, different specifications of the fan speed choice should distinguish somewhat, fundamental criterion is: on the premise of produce the same volume, the fan speed should be lower, the greater the noise will also small, regular in 3500 RPM to 5200 RPM speed is compared between the conventional.