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When buying a computer cooling fan, you can usually find fans of different interfaces. Common fans with 2 pin, 3 pin and 4 pin. What is the difference between them?




1.What is the Difference in 2 or 3 Wire vs 4 Wire CPU Fans?

Some Knowledge about 2 Pin Computer Fans


The 2-pin cooling fan means that it has only two red and black power cables.The structure is very simple and there is no variable frequency and speed change function. Now 2 pin cooling fans have been less to use, because the fan of 2 pin cannot meet the requirements in terms of shifting, etc., In contrast, 3 pin, 4 pin fan is the main stream now.


2.Advantages to 3 Pin vs 4 Pin Fans


3 Pin Computer Fan

The 3 connector fan is very common use in laptop, it can adjust the fan speed according to the CPU temperature, but the flexibility is poor. There are red and black power line based on the addition of a yellow or black yellow line, mainly for speed measurement, through the motherboard can detect whether the fan is rotating and speed of the fan.



Disadvantages of the 3 fan connector:

The speed adjustment of the 3 pin cooling fan is achieved by adjusting the fan voltage. In addition, it is necessary to confirm if the motherboard supports the speed regulation. It is obvious that 3-pin CPU fan adjustment speed is not flexible enough to reflect the status of the processor in real time, and various settings need to be made in the BIOS.


Different fans have different starting voltages, and the voltage regulation is not linear. The voltage control speed may cause the low voltage to fail to reach the required starting voltage of the fan, and the laptop fan may stop working.


When replacing the fan, you also need to consider whether the motherboard supports it, for example: whether 3 pin fans on 4 pin motherboards can work.


How Does 4 CPU Fan Connector Work?

The 4-pin cooling fan is based on the 3 pin and has a PWM line (pulse width modulation). The so-called PWM line uses the PWM mechanism to adjust the fan speed, and the fan voltage is constant, avoiding the control voltage to shift. The PWM fan does not need to rely on the motherboard BIOS, which is more convenient. The PWM pulse signal can output different duty cycle (Duty Cycle), and the duty cycle between 0-100% can adjust different fan speeds, so it can be accurately and flexibly controlled.


There are also low-speed PWM and high-speed PWM in PWM speed regulation. The low-frequency PWM measurement speed has a wider range, but there will be noise generated by fan commutation. In contrast, high-frequency PWM will be better overall.


If the 4 pin interface of some motherboards is not PWM, then even if the cooling fan is controlled by 4 pin PWM, it can't be intelligently controlled. Some motherboards may be voltage controlled.



Summary:

In laptops,almost all notebook fans use 3 pin or 4 pin connectors. If you want to replace your laptop fan, it is recommended that you buy 4 pin laptop fans, which is smarter and quieter than a 3-pin laptop fan. GEMWON is a professional laptop fan wholesaler, you can buy all brand original laptop fans here, including HP/Dell/Asus/MacBook.




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