Where is the chassis fan interface?

In fact, this is not familiar with the circuit of the user may not know the internal structure of the chassis, generally bought chassis fan, built-in 3PIN interface, but will bring a large 4PIN transfer wiring. Computer motherboard is a Sysfan interface, generally there are two interfaces are 3PIN interface, if your chassis fan is also 3PIN interface can be directly connected.

If it is a large 4PIN, it can be connected to the power supply, because the motherboard may be 3PIN is not connected. However, if the fan is fully connected to the 4PIN interface of the power supply, the fans will be unable to adjust the speed, and in full operation, the user is advised to purchase the fan governor to coordinate the use. But now there is also a fan with the speed to buy.