CPU-OPT VS CPU-FAN – What’s the difference?

CPU-OPT VS CPU-FAN – What’s the difference?

Upgrading your existing system or building a new one is both exciting and frustrating. This process is exciting if you already know what you are doing. However, if you are a newbie, connecting all the power cables can be quite a challenge.

It is certainly frustrating to install third-party CPU coolers and a powerful gaming CPU when there are two headers, and you don’t know which one to use.

CPU fans can be connected to either CPU-OPT or CPU-FAN. However, you have to be careful. Otherwise, it might lead to BIOS throwing out errors or the system not booting.

Below, we have discussed “CPU-OPT vs. CPU-FAN” to make it easy for you to decide which header is the best choice for you!

So without further ado, let’s get right into it!

What Is A Fan Header?

Let’s start with a little introduction: what is a fan header? What is CPU-FAN? And what is CPU-OPT?

Headers are the rows of pins that form the “male” connectors, onto which “female” connectors can attach. Fan headers are connectors that can be used to power water cooling systems or fan cooling systems. Originally, they were designed to power only fan cooling systems. However, now they have multiple uses!

What Is CPU-FAN?

What actually is a CPU fan? It is a tiny cooling system or fan that is connected to your motherboard. It is the job of a CPU fan to keep your system cool, from BIOS to the motherboard of your system.

When it comes to the CPU-FAN headers, different words have different meanings. The motherboard and different software like NZXT CAM and HWMonitor utilize this header to protect your system from our heating. Your system fan must be connected to this header; otherwise, you won’t be able to boot your device.

What Is CPU-OPT?

Different systems have different specifications and requirements. Depending on your usage, your computer might require multiple fans for proper functioning. In that scenario, you’ll see multiple headers on your device, allowing you to use an additional liquid cooling system with your standard system fan.

CPU-OPT is a secondary header that allows you to use a second fan or cooling system with your device. Even if you don’t have a secondary cooling system attached to the CPU-OPT header, your system will work properly. However, in case of overheating, a CPU-OPT header can alert you.

Difference Between CPU-FAN And CPU-OPT

Well, the most common difference between a CPU-FAN and a CPU-OPT is their usage. A CPU-FAN header is to connect the primary fan. Without a primary CPU cooler connected to the CPU-FAN header, your system won’t boot, and the BIOS will show an error.

On the flipside, the CPU-OPT header is designed to connect multiple CPU cooling fans. This one is also known as the CPU optional header. You don’t actually have to use any hardware with this header. Unlike the CPU-FAN header, your device will work perfectly even if you have not connected any water cooling pumps or other system fans with the CPU-OPT header.

When it comes to the CPU-FAN header, you don’t have an option. You must connect the primary cooling system of your machine with this header. However, CPU-OPT allows you to use more than one fan, depending on your usage and needs.

Here’s a great video by Tech Round Up that shows the difference with an example:


The SYS FAN header is designed to use with system fan. With this header, the system fan turns on and off according to when the motherboard heats up. The job of this header is to run the system cooling system at a constant fan speed.

Alternatively, a CHA-FAN header is designed to power the chassis fan, which is connected to the PC case’s exterior box. This fan can be mounted both internally and externally. Toward to case fan, the header is connected to the motherboard. Although 3-pin chassis fans are commonly used, you can also get 4-pin fans for better results.

While using a powerful graphics card, it is recommended to use both a chassis fan and a system fan. These two fan headers will keep your device cool and ensure efficient airflow. The CHA-FAN and SYS-FAN headers are completely independent, meaning you don’t have to connect them to your system’s principal fans. But, these headers will still monitor your device!


We hope the above-mentioned “CPU-FAN vs CPU-OPT” guide has helped you understand the difference between these headers. Even though both these headers are designed to power a cooling system, they are still quite different.

In a nutshell, the CPU-FAN header is for your core cooling system. With this header, you can connect your primary fan. It is necessary to connect the main fan with this header. Otherwise, your device won’t boot up.

CPU-FAN header is not the only header available on your computer. Besides this, you also get some other fan headers, including the CPU-OPT header. CPU-OPT header is an optional header that allows you to connect other fans with your system. It is recommended to use a fan hub with a CPU-OPT header to keep your device cool!

You don’t actually have to use a CPU-OPT header. All you need to do is connect a fan to your CPU_FAN header, and you are good to go. However, if you are using a powerful device, it is recommended to use an additional cooling system to protect your system from overheating.