what is cpu opt
CPU_OPT is a motherboard fan header, usually meant for a second CPU cooler fan or an AIO cooler pump/fan setup. It typically works alongside CPU_FAN so the motherboard can monitor and control cooling more cleanly.
What it does
- Connects an extra fan near the CPU cooler.
- Lets the motherboard control fan speed based on CPU temperature.
- Is often used for dual-fan air coolers or liquid cooling setups.
Common use cases
- Dual-tower CPU coolers with two fans.
- AIO liquid coolers, where one header may be used for the pump or the second fan.
- Extra CPU-area cooling when the main CPU_FAN header is already occupied.
Important note
CPU_OPT is usually optional , not required for the system to boot, but some motherboards may warn if the main CPU_FAN header is empty or not detecting a fan.
Simple rule
If you have one CPU fan, plug it into CPU_FAN. If you have a second fan or a pump that needs motherboard control, CPU_OPT is the usual place for it.