During the process of assembling a computer, although the installation is simple, problems often arise with the connections. Many users mistakenly plug the CPU cooler power cable into the SYS_FAN port. Although the fan may spin, you might encounter an F1 error message “CPU Fan Error” when starting the computer, and it also prevents the CPU cooler from intelligently adjusting its speed. Below, we share knowledge about the CPU_FAN, SYS_FAN, CHA_FAN, and CPU_OPT interfaces on computer motherboards.

Knowledge about CPU_FAN, SYS_FAN, CHA_FAN, and CPU_OPT Interfaces on Motherboards

1. CPU_FAN

CPU_FAN is a dedicated interface for the CPU cooler, operating at a voltage of 12V and using a 4PIN connector. The 4-pin fan has PWM intelligent speed control, which intelligently adjusts the fan speed based on load and temperature changes. Compared to a 3-pin fan, the additional wire is for speed regulation; the 3-pin fan does not have PWM control but can detect fan speed. The air cooling fan or the water cooling fan is connected to the CPU_FAN, which supports 4-pin PWM intelligent temperature control, helping to avoid excessive noise.

CPU_FAN

2. SYS_FAN

SYS_FAN, also known as the “system cooling fan port,” uses a 4PIN connector and is generally used for case fans. Some users add additional case fans for better internal cooling or to create airflow, which are connected to the SYS_FAN interface. If the case fan is 3-pin, it can still be plugged in, but it will lack the speed regulation wire.

Additionally, some motherboards have a CHA_FAN port, which is for case fans, but you can also use it to connect other 12V fans.

SYS_FAN

If there is only one CHA_FAN or SYS_FAN on the motherboard and multiple case fans to connect, and if these fans are all 4-pin, you can purchase a fan hub (FAN HUB) to achieve speed control or RGB synchronization.

3. CPU_OPT, aio_pump

CPU_OPT and aio pump are dedicated interfaces for water cooling pumps; if you have a split water cooling system, they are generally connected to the water pump.

There are also some lesser-known ones: chip_fan is for the northbridge fan, and PWR_FAN is for the power supply fan, which are generally not used.

In conclusion, this article shares knowledge about the CPU_FAN, SYS_FAN, CHA_FAN, and CPU_OPT interfaces on motherboards. As long as you understand the functions of these fan interfaces, the sockets are designed to prevent incorrect connections. We hope this article can help everyone.