The motherboard takes a full-size 24-pin ATX power link from the power supply, which handles most functions on the PC. Still, there's also a dedicated central processing unit (CPU) connection, usually located in the top-left, between the voltage regulator modules (VRMs) and rear I/O. Sometimes, you'll see more than two headers, consisting of an 8-pin and 4-pin or two 8-pin links. The question is; do you need to use all available headers or would using the standard 8-pin setup suffice for most PC builds and for the system to run stable?

What are these headers used for?

The 8-pin header near the top of the motherboard is used for supplying power to the processor. It's a dedicated link between the onboard VRMs and other power management components and your power supply, allowing the motherboard to provide clean power to the CPU as required. It's important to connect this header to your PSU else the system won't boot. Providing clean and reliable power to the CPU isn't a straightforward process as the component requires core voltage and auxiliary voltages for all available functions.

This link needs to be established, especially when overclocking or placing the system under heavier loads. The CPU is one of the most vital parts of any system, handling all the instruction processing. The more stable we make this CPU, the longer it should last. Think of it as providing power to your discrete GPU with the PCIe cables. The only difference is the GPU requires all available power headers to be utilized whereas you can technically get away with using just one 8-pin CPU_PWR header, even if the motherboard has additional ports.

Why do some motherboards have more than one?

You may be wondering why your motherboard has the aforementioned 8-pin CPU_PWR header, but there's also an additional 4-pin or 8-pin port. This setup is usually reserved for more advanced (and expensive) motherboards. It's an important factor to bear in mind when shopping around for motherboards and power supplies. Not all PSUs will have two cables for supplying power to the CPU. If not, you'll be running the system with only some of the ports in use. While this won't cause any immediate problems, you may find the system encountering an issue further down the road.

It's even more important for overclocking. When pushing the system to its limits (or above), you'll be throwing a lot of voltages and watts at the processor, which will pass through these CPU_PWR headers from the PSU. Each cable inside your system is only rated for a set wattage, which is also why we saw so many problems with the RTX 40 series cards and their special single connector handling 400W if not more.

Does it really matter how many you use?

It may not seem like it matters much and you likely won't notice much of a difference using the PC with the standard 8-pin connection active compared to it and the secondary header both online, but it's worth doing if you can. Should your motherboard either have an 8+4-pin or 8+8-pin for CPU_PWR, I recommend using the available cables with your PSU to populate all headers. This evenly distributes the power over two cables and plugs. This not only makes it more stable but can help reduce wear and heat buildup on either cable.

Even an 8+4-pin setup will allow for a 1.5 times the total power capacity, compared to a single 8-pin cable. Like GPU cables, we want to use as many cables and ports as possible to even the current load and reduce strain on all components.