Many people still can’t tell the difference between 2-pin, 3-pin and 4-pin fans. Huizhou Huihexing heat dissipation today

Types of cooling fans-2-pin, 3-pin, 4-pin

There are many ways to classify cooling fans, including DC and AC, as well as brushed and brushless, ball bearings, and oil-retaining bearings. Here we are mainly talking about the power cord interface of the cooling fan, which is simple It can be divided into 2 pins (2pin), 3 pins (3pin) and 4 pins (4pin). Let's look at them one by one.

2 pin, 3 pin and 4 pin of the cooling fan (picture from togell)

2-pin fan: simple and rude, but not capable of measuring speed

The 2-pin cooling fan means that it has only two power cords, one for grounding and one for power supply. The structure is simple, but it has few functions and cannot measure speed. If you want to adjust the speed, you need to use other solutions.

In addition to the 2-pin fan mentioned above, there is also a fan with a D-type power connector, that is, a fan with a large 4pin connector. Here is also classified as a 2-pin fan. The more representative fan is Cooler Black. Cyclone series.

This fan does not have a variable speed function, and the power supply is 12V. The large 4pin interface is used for better performance (more power). The speed of the cool black cyclone is 1200RPM and the air volume is 44.72CFM. Speaking of this, I think that because of the poor heat dissipation environment in the past few years, I bought a few violent fans with a speed of 1500RPM as soon as my head got hot. They also used a large 4pin interface. The air volume was really strong, but the noise couldn't stand the noise. I gave up after using it twice. .

At present, the 2-pin fan has not left the stage. There are still a large number of applications in different occasions. However, for DIY players, the 2-pin fan can no longer meet the requirements in terms of speed change, and 3-pin and 4-frame fans are the only ones. More suitable choice.

3-pin fan: VC voltage speed regulation, poor flexibility

The problem that the 2-pin fan cannot be adjusted in speed is becoming more and more serious in the current society, because people do not always need the fan to run at full speed. When the temperature is not high, reducing the fan speed can bring lower noise, and players have an increasing demand for silence. So there is a 3-pin fan interface that can adjust the speed.

The 3-pin fan interface adds a yellow line (also partly black, yellow and green) to the original red and black base. It is mainly responsible for speed measurement. The motherboard can detect whether the fan is rotating and how much it rotates, but the 3-pin fan The speed adjustment is achieved by adjusting the fan voltage. First of all, adjusting the speed is still not flexible enough. The temperature detection comes from the motherboard and cannot reflect the CPU status information in real time. It also requires the motherboard BIOS to set various parameters, so it depends on whether the speed can be adjusted. Whether the motherboard supports it or not.

More importantly, different fans have different starting voltages, and voltage speed regulation is not linear. Controlling the speed by voltage may cause problems such as failure of the starting voltage required by the fan when the voltage is low, and the fan stalls.

4-pin fan: more flexible and smarter speed regulation is here

From pin 2 to pin 3, the problem of fan speed regulation has not been completely solved. Therefore, in the LGA775 era, Intel co-manufacturers introduced a new PWM speed regulation specification. The cooling fan has become 4 pins, and there are more on the basis of 3 pins. One PWM line (pulse width modulation). The color of the 4-pin fan interface is also not fixed, there are two common ones:

Color and interface definition of 4-pin fan interface

The extra PWM line uses the PWM mechanism to adjust the fan speed, and the fan voltage is constant, avoiding a series of drawbacks of controlling the voltage to change speed.

In addition, the PWM pulse signal can output different duty cycles (Duty Cycle), and the duty cycle between 0-100% can adjust different fan speeds, so precise and flexible control can be achieved, while the PWM fan can do It does not depend on the motherboard BIOS and is easy to use.

The fans of mainstream radiators are all PWM types

When it comes to PWM speed regulation, there are actually many specific technical classifications. PWM also has low-speed PWM and high-speed PWM. The low-frequency PWM measurement speed has a wider range, but there will be fan commutation noise, which is relatively high. Frequency PWM will perform better overall.

Mutual insertion of 3-pin and 4-pin fans and interfaces and precautions

Sometimes, even if the fan is controlled by 4-pin PWM, the speed cannot be controlled intelligently when connected to the motherboard. This problem may have something to do with the motherboard, because the 4-pin ports on the motherboard are not necessarily all PWM controlled. It is also possible that the voltage controls the speed.

to sum up:

The 2-pin, 3-pin, and 4-pin of the cooling fan are old-fashioned problems. At present, 2-pin fans are rare in daily use. There are more of 3-pin and 4-pin. From the experience of use, choose the 4 with PWM function. Pin fans and motherboards are the first choice. Fortunately, this is not a problem now. Most motherboards and CPU coolers have 4-pin PWM fans.