Two kinds of "220V Cooling Fan" The difference is that the air flow in the form of different forms, is generated when the blast of turbulence, wind pressure resistance but susceptible to loss; generated when ventilation is laminar flow, pressure small but steady flow . In theory, the turbulent heat transfer efficiency is much greater than the laminar flow, and therefore did not become mainstream design form. But the flow of movement and the heat sink has a direct relationship. In some "220V Cooling Fan" heat sink design, airflow obstruction by very large heat sink, then the use of ventilation may have better results. The only problem with the design of the side of the blast, not usually at the top of the blast and the effect of any difference. The improved method is more effective to establish "220V Cooling Fan" CPU dedicated cooling duct, so they are not affected by the hot air near the CPU, the equivalent of reducing the ambient temperature.