Explaining the cables in your computer’s power supply
So you’re building a new gaming PC. This can be a daunting task for a novice. After all, there are a lot of components, and if you don’t know what you’re doing, you can screw things up. Therefore, it is important to familiarize yourself with all the components inside the computer, how they work and what is located where.
Case in point: the power supply you just unpacked and the mess of cables coming out of it. What are all these PSU cables and connectors and what do they do?
20/24 pin cable to motherboard
First, the cable that you’re probably most interested in is the wide 24-pin, whether you bought a modular or non-modular PSU. And that’s actually the most important cable.
This cable is the main connector that provides power to your computer’s motherboard. While it’s not the only connector your computer needs (other components will require additional power, as you’ll soon see), it’s the main one responsible for supplying the correct voltage to your motherboard, and by extension most of your PC’s components. . This includes your RAM, storage devices, non-powered PCIe devices, and pretty much everything else on your motherboard.
You’ll usually find this connector in a prominent location around the edge of your motherboard. On older ATX motherboards, as well as lower end ones, you’ll find that the main connector is actually 20 pins instead of 24. Likewise, some power supplies have a 20+4 connector (with 4 pins that can be separated) instead of a straight 24 pin. This is because older computers with lower power requirements get by with 20 pins instead of 24, and power supplies mostly stay the same over the years (and not for lack of trying).
PSUs are more or less compatible with older ones thanks to the ATX standard, and this has stuck in the minds of some PSU manufacturers. After all, old power supplies will die eventually, and when they do, being able to use a new power supply can probably save them from ending up in a landfill.
4/8 pin CPU connector
Then we have the CPU connector. The CPU is one of the few parts of your PC that needs auxiliary power beyond your motherboard’s power supply. The CPU connector is there to intervene.
The CPU connector is usually located near the CPU socket of your computer. Once you’re done with the motherboard connector, just plug it in and you’re good to go.
Depending on the computer, this connector may be slightly different. In lower-end computers, you will find a 4-pin connector on the motherboard, which should be able to provide enough electricity for these lower-end chips. On mid-range and high-end CPUs, you can expect to find an 8-pin instead, which gives enough power to almost any chip.
Your computer’s power supply will almost always have an 8-pin connector that splits into two, known as a 4+4-pin. This allows for connection to both 4-pin and 8-pin connectors – just put one away when you don’t need to use it.
You may find more than one CPU cable in some power supplies. Similarly, some motherboards may include an 8-pin and a 4-pin connector, or may come with a 12-pin instead. Although not the norm, some computers need a lot of CPU juice, especially for people who like to overclock.
6/8-pin PCI Express cable (GPU cable)
Technically, all PCI Express power needs are already provided by the motherboard connector. If you put something like a Wi-Fi card in there, it will work perfectly. However, some devices (most commonly GPUs) need additional auxiliary power beyond what the motherboard provides. This is where PCIe cables come in. They are sometimes called GPU cables because they are mainly used by GPUs.
They will be available in 6-pin and 8-pin variants and connect to the GPU. Depending on which GPU we’re talking about, you can get by with a single connector, or you might need two or a whopping three, depending on the power requirements of the particular card. If the card’s requirements are not fully met, users may experience a drop in performance or even instability and frequent crashes. Fortunately, most PSUs, especially higher power ones, come with multiple PSU cables.
In addition to the traditional 6/8-pin PCIE cable, you may also encounter newer 12VHPWR or 12V-2×6 GPU cables used in modern GPUs such as Nvidia’s RTX 40 series.
12/16 Pin GPU Cable (12VHPWR)
The 12VHPWR (12V high-power) connector was introduced with the launch of PCIe 5.0 and the Nvidia RTX 40 series GPUs. This connector delivers up to 600W of power through a single cable, replacing the need for multiple 8-pin connectors on high-end GPUs. The connector contains 12 larger pins that handle power and four smaller data pins. These data pins allow the power supply to communicate with the GPU and adjust the power supply based on demand.
However, despite its compact design and promise of simplified cabling, the 12VHPWR has had its share of problems, particularly with Nvidia RTX 4090 cards. Some users have reported melting connectors, mainly caused by incorrect cable insertion. To address these concerns, PCI-SIG, the organization behind the PCIe standards, revised the 12VHPWR connector, leading to the development of the 12V-2×6 variant.
12-pin GPU cable (12V-2×6)
12V-2×6 is a revision of the 12VHPWR connector, designed for increased safety and reliability. It maintains the same power delivery capacity of up to 600W while adding critical features that compensate for the weaknesses of 12VHPWR connectors.
For example, the data pins in the 12V-2×6 connector are 0.25 mm shorter and the power terminals are 1.5 mm longer. This design change reduces the risk of mis-insertion, which was the primary cause of overheating seen with the 12VHPWR.
Another advantage of the 12V-2×6 connector is backward compatibility with the original 12VHPWR. If your GPU or PSU uses a 12VHPWR connector, it will still work with the newer 12V-2×6 standard. This ensures you won’t need to upgrade your power supply if you’re upgrading to a newer 12V-2×6 GPU, provided your PSU is PCIe 5.0 compatible.
The goal of these revisions is to fix issues while maintaining the simplified cabling setup that benefits high-performance gaming rigs. As new GPU versions still require high performance, this connector development ensures that your system remains reliable even under heavy load.
Additional PSU cables
While these are the three main cables you need to know about, there are some others that you may or may not need depending on your use case. These are in charge of powering the secondary components in your PC.
SATA cable
First we have the SATA power cable. These are still widely included in power supplies today, and if the name SATA tells you what they’re for, then your hunch is probably correct. The SATA power cable provides power to the hard drive or other SATA drive directly from the hard drive. Not to be confused with the SATA cable, which is the actual connection between your hard drive and your computer – the SATA power cable provides power, while the SATA cable provides everything else.
SATA power cables have other uses as well. For example, some RGB-addressable computer cases may have a hub to connect all cables from RGB peripherals such as fans. In that case, this RGB hub will probably be powered by a SATA power cable, even if it’s not a drive. It can be used as an auxiliary power supply for many peripherals.
Molex
Molex is largely deprecated these days, but you may still see it on older or lower end computers. Like SATA, Molex connectors are designed to provide auxiliary power. They used to be present in everything from hard drives to case fans.
Over the past decade, however, Molex has largely disappeared. Reason? It is generally considered a nuisance connector that breaks easily and is unreliable. Those use cases that still need a Molex-like auxiliary power supply have since moved to SATA.
Knowing what each power connector coming out of your power supply does is just as important as knowing how efficient it is to build your computer the right way. Hopefully with our explainer it’s pretty clear now.