What are the 4 wires of the computer CPU cooling fan?

Some of our computer’s cooling fans have 4 lines, and they are mainly used for heat dissipation on the CPU, so why does the cooling fan on the CPU have 4 lines, while others such as the chassis and power supply have only 2 lines. What are the lines used for? The real 4-wire cooling fan is a smart fan. Generally, the red wire is the positive pole of the power supply, the black wire is the negative pole of the power supply, the yellow wire is the FG pole, which is the signal line for speed monitoring, and the green wire is the PWM line, which automatically adjusts the frequency of the computer. A function line for the speed of the cooling fan, remove the latter two lines, the cooling fan is also running, but two functions are missing. Adding the PWM function can effectively increase the service life of the cooling fan. More importantly, when we are using a low CPU frequency, the system will automatically lower the speed of the cooling fan to make the cooling fan quieter. Welcome to the heat dissipation classroom and news center of the cooling fan manufacturer again. The copyright belongs to the cooling fan manufacturer and represents only personal opinions. Please do not reprint the whole article. Any violation will be held for legal responsibility. If you need to know more about the cooling fan manufacturer's product introduction, please Click on the product center