Ordinary cars always have two central fans that can be installed. The front one is at the hard drive bay, and the rear one is under the power supply and above the keyboard port. Higher-priced cars have 1 to 2 fans installed at the factory. When installing a car fan, the principle of air movement should be followed. If the fan of the device travels and exits, the air path inside the car is very regular from front to back; if the fan device is reversed, and the fan is inverted, the fan is in the back, the front is out, or the fan is in the back. When only one car fan is installed, it depends on your heat dissipation requirements whether to dissipate heat for the hard disk or the whole machine. Many fans are installed in the rear fan position by default, and they are exhausted, which is indeed reasonable. The indoor ambient temperature is 23 degrees, and the result is that the air supply and exhaust car temperatures are both 35 degrees, but the CPU temperature when the air is 61 degrees, and only 56 degrees when the air is exhausted, there is an amazing 5 degrees difference! To analyze the reason for this situation, the main reason is that the high-temperature air above the mosfet pipe in the power supply area of u200bu200bthe motherboard is brought to the CPU area and then sucked in by the CPU fan, causing the CPU temperature to remain high. When changing to a ventilation system, the hot air above the mosfet tube flows directly to the outside of the car and does not pass over the CPU area. In addition, the ventilation is not only beneficial to the CPU temperature. Because it is simultaneously exhausted with the power supply fan, a certain negative pressure is formed inside the car. The cold air from the outside will enter the internal supplement through the empty fan port in front, and then the hard disk, memory, and graphics card will get A certain level of cooling. This is more obvious than the short circuit where the air flows from the outside through the car fan when the wind blows, and then is discharged from the power supply fan after passing through the CPU area. In fact, the wind path at this time is basically the same as when the two car fans move in and out, except that the air volume and breeze pressure are slightly lower, and the airflow speed inside the car is lower.