"220V Cooling Fan" main role is the heat, and the heat sink is required by forced convection fan to speed up heat dissipation, so a fan of good or bad, on the whole cooling effect plays a decisive role. Equipped with an excellent performance of the CPU fan is one of the key factors to ensure the smooth functioning of the entire computer. "220V Cooling Fan" speed is the number of revolutions per minute of the fan blades, the unit is rpm. Fan speed is determined by the motor inside the coil turns, voltage, number of fan blades, inclination, height, diameter and bearing systems. Speed ??and "220V Cooling Fan" quality is not necessarily linked. Fan speed can be measured by the internal speed signal, can also be measured by the outside.