In this article, we will talk about everything PCIe cables. The power supply unit is probably the most important part of any computer or server. It must be able to provide stable voltage and current according to the power needs of different components that are part of the computer. The PCIe cables are part of the power supply system and are used to deliver voltage and power to PCIe devices like the graphics card.
So in this article, we are going to cover a lot of information about PCIe cables. We will talk about what a PCIe cable is, what kind of PCIe cables are available in the market, where and how to plug them, and so on. So, let’s start with it…
What are PCIe cables?
PCIe cables are a part of the PSU (Power Supply Unit) and are used to power PCI cards that need more power, like a graphics card.
The PCIex16 slots provide 75 watts to the PCI Express expansion cards that you plug in, and more often than not, it’s sufficient to power up low-demanding graphics cards or other expansion cards like sound cards or network cards. But if you are planning to use more power-hungry graphics cards like the Nvidia GeForce RTX 3060 Ti, you will need a PCI cable to supply additional power.
So before you buy your power supply unit, you should know exactly how many and what kind of PCIe cables you need and plan your system accordingly.
And this brings us to the next question.
Related Article: Does it matter which PCIe x16 slot I use?
What kind of PCIe cables are available?
As you can understand, there is not only one but many different kinds of PCIe cables available in the market.
The main difference between PCIe cables is their number of pins and the maximum amount of power they can provide.
The most commonly available PCIe cable comes in 6, 8, and 12-pin variants, with 8 pins being more common these days.
6-Pin Power Cables
The 6-pin power cables provide a maximum power of 75 watts and are used to power up graphics cards that don’t need a lot of power.
8-Pin Power Cables
The 8-pin PCIe cables can power up devices with a maximum power consumption of 150 watts and are best suited for high-performance gaming or mining machines. These cables are able to handle PCI express graphics cards that require a lot of power to work properly. They can be purchased as a straight 8-pin cable or 6+2 cable.
12-Pin Power Cables
The 12-pin PCIe cables provide a maximum power of 600 watts depending on the cable and are mainly used for overclocking or mining machines.
Pigtail Power Cables
The pigtail PCIe cables are cables that one end connects to the power supply, and the other end is split into two cables. It can be split into two 6 or 8-pin cables, depending model you buy. These cables are best suited for powering up low-power graphics cards and are not recommended if you have a high-end graphics card because they deliver less power compared to straight cables.
Related Article: PCIe 2.0 VS 3.0 – What Is The Difference?
Combabilty of GPU Connectors
If your power supply unit is old and doesn’t have a PCIe cable that can handle the power your graphics card needs and you don’t want to buy a new power supply unit, you can always use an adapter.
These adapters are called Molex-PCIe adapters and can be used to connect a 6-pin cable to an 8-pin graphics card or an 8-pin cable to a 12-pin graphics card. While these adaptors will make the cable able to connect to the graphics card, they won’t provide enough power and can be dangerous, and we strongly advise against using them!
How many PCIe cables do I need in a PC?
This is a question you need to ask yourself early in designing your PC.
The main thing to consider is how many and what kind of GPUs you are going to use in the future and if you are planning on overclocking.
Let’s say that the PC you are building will only have one graphics card at the beginning, but in the future, you might want to add another graphics card.
The graphics card you are going to buy will need one 8-pin power connector, so you will buy a PSU with one 8-pin PCIe power cable, sounds good, right? But if you plan to buy the same graphics card in the future, why not plan ahead and buy a power supply unit that has at least two 8-pin PCIe cables, so you won’t have to change your power supply unit in the future?
If you are building a mining rig that will use a lot of high-end GPUs that might need up to three 8-pin PCIe cables each, it is better to buy a high-power modular power supply unit that has an ample amount of sockets. This way, you can plug in the exact number of PCI express cables you need, and later if you want to add another graphics card, you can just plug in an extra cable or two instead of buying a whole new power supply unit.
On the other hand, if you are not a gamer and don’t plan on using a demanding power-hungry graphics card, then you won’t need a PCIe power cable, as the PCIe x16 slot will provide all the power your graphics card needs.
The PSU is one of the most important components of your PC, if not the most important, and we strongly suggest going the extra mile to get a really high-quality one.
Remember that the PSU provides your computer components with electricity, so if your PSU is not good enough, it can lead to damaged hardware and accidents.
Related Article: What Are PCIe x1 Slots And What They Are Used For
How to connect a PCIe cable to my GPU?
Connecting a PCIe cable is a really straightforward process; all you need to do is find the PCIe cable in your PSU and plug it in on your graphics card power connector.
To find the PCIe cables, you can either look for them on the PSU manual or directly on the PSU itself.
Most PSUs will have plenty of PCIe cables, so choose one of them and plug it in on your graphics card power connector.
Related Article: How To Connect Power Supply To Motherboard In Easy Steps
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PCIe cables are mainly used to provide additional power to GPUs beyond the maximum power that the PCIe x16 slot can provide, and they come in different types with different numbers of pins and voltage.
The number of PCIe cables that your computer needs depends on the type and number of GPUs you will use in the future and how much power they will need.
If you have a high-end graphics card, it might be a good idea to buy a high-wattage PSU with an ample number of PCIe cables, so in the future, if you add another GPU, you can just plug another cable in instead of having to buy a new PSU.
Overall you should invest in a good PSU that will provide the power your GPUs need and have room for adding more PCIe cables in case you want to add another GPU.
Let us know if this article was helpful or if you think anything needs to be added. We are always open to suggestions!
Nick Ryley, is a computer architect and the owner of The Pc Geekz.
His love to play games got him interested in computers in the first place. He wanted to be able to build a gaming PC that could run all the latest games at max settings and this has him pursuing a major in computer architecture!
He started this blog to help people out and answer some of the most common questions about computer building