What’s the Difference Between CPU Fan And CPU OPT Fan?

In this article, we will discuss the two distinct yet quite similar headers on your motherboard that both appear to relate to a CPU fan.

To summarize, the standard CPU fan is designed to be the primary fan for cooling your CPU. CPU OPT fan is used as an additional fan in case you need more than one connection for a separate CPU cooling solution.

Why exactly are they referred to as that way? Can they be interchanged? And what about the other enthusiastic connectors in my motherboard? Read on below.

What Is A CPU Fan Header?

Commonly designated as CPU_FAN, this is a vital connection pin on your motherboard dedicated to a fan designed to cool the CPU.

It has four pins, which provide power, ground, sensing, and speed control features. It also has a notch on one side, so that the connector on the fan can only be plugged onto it in a sole orientation.

While the pin configuration of the CPU fan header is the same as with most fan headers on the motherboard, the particular CPU_FAN header has a built-in check and protection.

If there is no attached fan to it, the system will assume that your CPU does not have a cooling mechanism installed, and will refuse to correctly boot.

Furthermore, the CPU_FAN port will typically be located near the CPU’s cooling system (near the VRMs, or next to the DIMM slots).

The location is usually suitable enough so that the wires can be effortlessly routed for ideal cable management.

What Is A CPU OPT Fan Header?

This one is recognized as CPU_OPT, which means CPU Voluntary. As the name suggests, it is an extra section set aside for non-vital configurations for CPU cooling solutions.

A basic example is when the cooler has more than one fan. Coolers like DeepCool’s AK620 or Arctic’s Freezer eSports 34 Duo come with two distinct 120mm fans.

All enthusiasts will have their individual connectors, with one connected to the main CPU_FAN port, and the other connected to the CPU_OPT port.

While the CPU OPT fan header does not have the same boot time safeguard as the primary CPU fan header, it can still provide vital monitoring and crucial diagnostic functions.

At the very least, the connector can tell if the fan attached to it has a potential malfunction.

Can You Use The Two Fan Headers Interchangeably?

If the connected devices are alike, then you can exchange them anytime.

But if the connections are separate, such as when linking fans and pumps from AIOs, then it is recommended to plug the fan to the main CPU_FAN header for less confusing diagnostics.

What About The Other Fan Headers On The Motherboard?

CHA_FAN and SYS_FAN are designated for chassis fans and system fans correspondingly. These are allocated for more flexible or durable fans.

It is satisfying to note that even though these headers have distinct labels, you can actually mix and match suitable hardware between them.

Simply ensure that the fans in the case are built and positioned to provide the optimal airflow essential for your computer.