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 conventional CPU fan is designed to be the primary fan for cooling your CPU. CPU OPT fan is used as an auxiliary fan in case you need more than one connection for a different CPU cooling solution.
Why exactly are they referred to as that way? Can they be interchanged? And what about the other fervent connectors in my motherboard? Read on below.
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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 velocity control features. It also has a notch on one side, so that the connector on the fan can only be plugged onto it on one orientation.
While the pin configuration of the CPU fan header is the same as with most fan headers on the motherboard, the specific CPU_FAN header has a built-in check and safeguard.
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 properly boot.
Furthermore, the CPU_FAN port will typically be situated near the CPU’s cooling system (near the VRMs, or adjacent to the DIMM slots).
The location is typically sufficient enough so that the wires can be easily routed for optimal cable management.
What Is A CPU OPT Fan Header?
This one is recognized as CPU_OPT, which means CPU Voluntary. As the name implies, it is an additional section set aside for non-basic configurations for CPU cooling solutions.
A straightforward 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 aficionados will have their personal 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 fundamental monitoring and vital diagnostic functions.
At the very least, the connector can tell if the fan connected to it has a potential malfunction.
Can You Use The Two Fan Headers Interchangeably?
If the connected devices are comparable, then you can swap them anytime.
But if the connections are separate, such as when linking fans and pumps from AIOs, then it is suggested to plug the fan to the primary 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 gratifying to note that even though these headers have individual labels, you can actually mix and match compatible hardware between them.
Simply ensure that the fans in the case are built and positioned to provide the optimal airflow necessary for your computer.
