What are PCIe Cables Used For? [Guide]

What are PCIe Cables Used For

PCIe cables are responsible for providing power to installed graphics cards and other large expansion cards. They come directly from the power supply unit to the expansion cards or the graphics cards. A typical PCIe slot that you install a graphics card on supplies 75 watts of power. This is usually not enough for many graphic cards.

PCIe cables are how you can bridge this power gap. PCIe cables can help you meet the power required by large and demanding graphics cards. The graphics cards you have will determine the number of PCIe cables you need.

So, we will be showing you in detail what PCIe cables are used for and how you can work around their connections. Stay glued as we brief you with all the necessary details.

What are PCIe cables used for?

Just as we have said, PCIe cables are used in the connection of power demanding devices. This device can be a graphics card, so PCIe cables can be used to connect them to the power supply unit. For most expansion cards, the power provided by the PCIe slot is more than sufficient.

However, for demanding cards like graphics cards, the power provided by the PCIe slot is not enough. Medium and high-end graphics cards might need more power from the PCIe cables. Not all cards require the use of PCIe cables. Some low-end cards might not need the aid of a PCIe cable.

An example of a low-end card will be NVIDIA GT 710. This is a very basic card that helps with video output on your computer. It also adds extra monitor capability for your computer. This card can not be used for running games and as such, it requires very little power. So, this card does need an external power cable. The power from the PCIe cable is sufficient.

So, it is important to check the power requirements of whatever PCIe cable you want to check. This will help you know whether it will serve your graphics cards.

How to Connect a PCIe Cable to an Expansion Card?

We have already seen how some PCIe devices may need extra power. This power comes from the power supply unit. The PCIe cable will come in handy to help with this connection.

You simply do this by routing the cable from your power supply unit and plugging it into your PCIe card. It should work once you plug it in correctly. The devices that need this routing are high-performance graphic cards.

Power supply units come alongside PCIe cables. The number of PCIe cables that you will need for this routing connection will be based on the model of your PSU. The widely accepted power supply units for workstations and gamers are modular power supply units. These power supply units come with additional connectors in case you need more PCIe cables.

An example will be if your power supply unit comes with 6+2 pin power cables that are ready to use. This means that you can work with graphics cards that have a 2×8 pin power requirement. If you want to add a card that has a higher power requirement, you can work with the modular supply units.

This modular supply unit comes with extra power sockets because of its modular nature. This means that you can connect more PCIe cables if you need to. The graphics card you have will determine the kind of PCIe cables you need. It will also determine the number of PCIe cables you need. You will find information about the power connector of the graphics cards in the manual. You can also contact your manufacturer for this detail.

You must also ensure that your power supply unit has a sufficient rating. High-performance cards will require a lot of power to run. It, therefore, means that the power supply unit of your computer must come with a good enough rating. Otherwise, you will experience a drop in performance.

Related: How to Tell if Your Motherboard is Bad or Dead

The Basic Types of PCIe Power Cables

There are different types of PCIe power cables available in the market today. They can be distinguished by their pin configuration and power supply rating. So, let’s look at a few of the power supply cables we have.

1. The 6-pin power cables

These cables are the smallest. This means that the power they can also supply is quite low. They can deliver the power of up to 75 watts.

2. The 8-pin power cables

The eight-pin cables can deliver a power capacity of up to 150 watts. You might just be wondering how do these cables double the power capacity of the 6-pin cables without doubling the number of pins. The fact is not all the pins present in the cable are for delivering power. Some pins serve as sensors.

3. The 6+2 pin cables

These cables function like eight-pin power cables. The difference is that they can deliver both lower and higher power capacity based on the requirements of the graphics cards. So, they offer you more flexibility than an eight-pin power cable.

4. The 12-pin cables

These are recent innovations in the line of connectors. They were developed by NVIDIA to cater for the RTX 3000 graphics cards. They are in limited supply and are only found in high-end computers. These cables can supply between 500 and 600 watts of power

5. PCIe pigtail cables

These cables have one end connected to the power supply unit. The other end is usually split into two connectors on the other side.

Related: Can You Use Nvidia Graphics Card with AMD Processor

Frequently Asked Questions (FAQs)

How many PCIe cables do I need?

The number and type of PCIe cable you need are dependent on the number of graphics cards you have installed on your computer. Some graphic cards do not even require these cables. So, it all depends on your graphics cards.

Will a pigtail power cable function less than an individual cable?

There have been several considerations on whether to settle for pigtail cables or individual cables. The truth is there is no difference. There have been no signs of drops in performance in either of the cables. So, whichever one you opt for will be down to your preference.


We believe that you should have a clear understanding of what PCIe cables are used for. We have shown you how they are needed to supply power for your graphics cards.

So, follow through with our guidelines. You will certainly have no issues whatsoever.

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