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A computer fan, also known as a cooling fan, is used to cool the computer case. It can be installed inside or outside the case and is responsible for bringing in cooler air and expelling hot air from the interior of the case. This helps to cool down other components through the use of heat sinks. Axial fans are commonly used in computers, while centrifugal fans are sometimes used. Cooling fans come in standard sizes and are powered and controlled through 3-pin or 4-pin electronic connectors. In recent years, cooling fans have not only improved their basic functions such as noise reduction and power consumption, but have also evolved into a variety of styles and designs with lighting effects.

Open-air and blower-style

There are two types of GPU fans: open-air and blower-style. Both types of fans serve the same purpose, which is to bring in cool air from outside to cool the GPU and expel the heat generated by the GPU out of the computer. However, these two fans differ in their design. Open-air fans can suck in cool air and expel hot air from the hollow space on the side of the GPU. Blower-style fans can expel hot air from a dedicated channel while bringing in cool air through the fan to help cool the GPU, and then expel the hot air out of the channel.


Airflow CFM

Airflow refers to the total volume of air that is discharged or taken in by the cooling fan per minute. If calculated in cubic feet, the unit of airflow is CFM; if calculated in cubic meters, it is CMM.
The higher the gas flow rate of the fan, the better, as it can increase the air circulation and improve the cooling effect. However, fans with high airflow may produce a lot of noise, and a balance between speed, airflow, and noise must be considered. CFM (approximately 0.028 cubic meters per minute) is the commonly used airflow unit for cooling fans.
Airflow is the most important indicator of the cooling capacity of a cooling fan. The specific heat capacity ratio of air is constant, and a higher airflow, meaning more air in a unit of time, can take away more heat. Of course, the cooling effect and the flow of air depend on the airflow in the same situation.

Fan speed RPM

RPM (rotations per minute) refers to the number of times a computer fan can rotate in one minute. Fan speed is determined by the number of wire coils inside the motor, working voltage, the number of fan blades, tilt angle, height, diameter, and bearing system. There is no necessary connection between fan speed and quality. The fan's speed can be measured by internal speed signals or externally.
From a technical standpoint, the higher the fan speed, the better the performance. When the fan rotates faster, it can blow more hot air away and bring in more cold air.

Fan noise

The noise value is a measure of the sound level in decibels (dB). The higher the noise value, the louder the fan noise.
In addition to the cooling effect, fan noise is also a widely concerned issue. Fan noise refers to the size of the noise generated when the fan is working, which is affected by multiple factors. Measuring fan noise needs to be carried out in a soundproof room where the noise is less than 17 dB, one meter away from the fan, and aligning with the fan's air intake along the fan's axis, using A-weighting. The spectral characteristics of fan noise are also essential. Therefore, a spectrum analyzer is required to record the fan's noise frequency distribution. Generally, the fan's noise should be as small as possible and there should be no abnormal noise.

Wind Pressure

Wind pressure and wind volume are two relative concepts. Generally speaking, to design a fan with a large wind volume, some wind pressure must be sacrificed. If the fan can drive a large amount of airflow, but the wind pressure is low, the wind will not blow to the bottom of the radiator. This is why some fans with high speed and large wind volume have poor heat dissipation performance. On the contrary, high wind pressure often means small wind volume, and there is not enough cold air and heat sink fins for heat exchange, which can also cause poor heat dissipation.
Dynatron has developed a fan blade design process that optimizes the efficiency and noise of the blade shape by calculating and combining blade loads, multiple impellers, and guide vanes according to the specified pressure/flow rate of the fan at the operating point. Therefore, the efficiency and noise balance of the fan can be fine-tuned according to the needs of customers.

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