"220V AC Cooling Fan" of life by motor life, environment, power supply and other factors of the composition. Air in the form of the most widely used form of axial fan is blowing down (which is the most common kind of fan), the reason why so popular is because of the combined effect of good and inexpensive. If the direction of the axial fan in turn, becomes upward ventilation, especially in certain models of the radiator will use this form. "220V AC Cooling Fan" The difference is that the two forms of air flow in the form of different turbulence is generated when the blast, but susceptible to wind pressure resistance big loss; generated when ventilation is laminar, but little pressure airflow stable. 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 AC Cooling Fan" heat sink design (such as too closely fins), airflow obstruction by the heat sink is very large, this time using the 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 a dedicated CPU cooling duct, so they are not affected by the hot air near the CPU, the equivalent of reducing the ambient temperature.