In the computer mainframe we use everyday, I wonder if anyone noticed the cooling fans, especially the CPU fans, some of which are two lines and some of which are four lines. So, why is the cooling fan on the CPU four wires? For example, there are only two lines for other cooling fans in the chassis.What are the extra lines for?

        The four-wire cooling fan is an intelligent speed-regulating fan.Generally, the red line is the positive pole of the power supply, the black line is the negative pole of the power supply, the yellow line is the FG pole, it is the signal line for speed monitoring, and the green line is the PWM line.It is a functional line for the computer to automatically adjust the speed of the cooling fan by removing the latter two lines, only two functions are missing, and the cooling fan can operate normally.

        Adding PWM function to the cooling fan can effectively improve the service life of the cooling fan.More importantly, when we use the CPU less frequently, the system will automatically turn down the speed of the cooling fan to make the cooling fan quieter and more energy-saving.