PCIe components need to be powered, just like any other component on the motherboard. Usually, their power comes from the PCIe slot. However, some components need more juice and this is why you may be wondering how many PCIe cables do I need.
Firstly, PCIe units that need power supply are the intensive ones. These include some graphics cards. The number of cables you need depends on the model of the card, its power requirements, and whether or not you need extra cables for aesthetic purposes.
The power supplies themselves do not directly affect the speed of the component they are connected to. As long as your device gets enough power, you will be running efficiently.
However, using one or two power supply cables can have an impact on performance.
How Many PCIe Cables Do I Need?
The actual number of PCIe cables you will need depends on several factors. The card itself is one of the determinants.
Some cards, including some low to midrange graphics cards, do not require external power supplies. Instead, they can run on the power supplied from the motherboard via their PCIe slots.
So, in reality, many expansion cards will not require any external power, so you will likely not be using any cables.
What Uses PCIe Cables?
As mentioned, the most important expansion card that uses PCIe power cables is the graphics card since many mid to high range graphics cards draw far more power than the 75W provided by the PCIe X16 slot.
Therefore, the amount of PCIe cables and the type of connector you need would depend entirely upon the graphics card you intsall.
The following talks about the various PCIe connectors:
PCIe Power Cables and Connector Types
Most people use PCIe cables to deliver power to very powerful expansion cards. Ideally, these include the graphics card. These units and CPUs have some of the highest power requirements on your motherboard because of all the data they crunch.
With the graphics card, knowing how many PCIe cables do I need is pretty straightforward. You will need to look at the power inputs of the card to find out.
This can also be determined from the card’s spec sheet as it will outline details about the card’s performance and requirements.
There are different variants of the PCIe cable. Their configurations and power ratings make them account for how many PCIe cables do I need.
Nevertheless, there are two kinds of connectors on a graphics card and these determine the cables you will need.
Different cards have different power requirements. The 6-Pin connector is suited for cards that require about 75 watts of power.
This is the most common connector used by many mid-range cards as it allows you to get 75W from the power supply and if more power is needed, it will be supplied via the PCIe X16 slot. The slot is capable of supplying a maximum of 75 Watts as well.
That said, if your graphics card has power requirements of anywhere between 75 and 150 Watts, you will likely have one 6-pin connector and for this, you will need only one PCIe cable to supply the needed energy.
The 8-Pin connector is typically found on cards that have more power requirements. It is capable of supplying up to 150W from the 12V rail on the PSU to the graphics card.
With 8 pins, you get the chance to run more intensive cards that draw a lot more power from the system. For this, you will also need just one PCIe cable, unless you are running top-of-the-line cards.
The 8-pin cable comes in two flavors. You can get one that has a single 8-pin connector in one terminal. The other comes as a 6-pin module with an extra 2-pin attachment. This one is more modular and can be used on both 8-pin and 6-pin cards.
This is used by some of the newer cards like the lineup from NVIDIA’s RTX 3000 series. These may need an adapter since many PSUs don’t have the required connectors.
On some cards, you get more than one connector. Sometimes they are different as well. For example, NVIDIA’s GeForce GTX 1080TI graphics cards come with two connectors. An 8-pin connector and a 6-pin connector.
You can’t use the same cable for both. In this case, you will need two cables to power the graphics card. And, because it has high power needs, about 250 Watts, the 300W supplied to it will be sufficient.
Cards also come with dual 8-pin as well as dual 6-pin connectors. It all depends on the needs but in each case, you will need to have two cables to supply the power. You can also use one Pigtail cable.
While you can use two independent cables to deliver power to your card if it has two separate power connectors, some people may prefer to use just one cable. This is where pigtail cables come in.
These have one end connecting to a single 8-pin connector on the PSU and the terminal end is split into two connectors.
With this, you will need just one cable to supply power to both PCIe connectors on the PCIe card.
Adapters and Aesthetics
You may need more cables if you’re building a setup with custom PCIe cables. They can be extensions of the provided cables, but this might end up doubling your cable needs.
Also, some PSUs do not have the power connectors you might need for your card. To get around this, users can install an adapter in the available slots and connect their power cables to it. This will allow the connection of more standard power supplies.
If you use an old PSU, you can increase the PCIe power cable by using a Molex adapter.
Also Read: Best Motherboards for VR
PCIe Power Cable and Performance Affect
To know exactly how many PCIe cables do I need, users need to understand their cards and power supply units.
PSUs connection to various components on your computer. Depending on the card, you can have different power connectors which may require you to have different cables.
Furthermore, you may end up needing an adapter to convert the available power connectors to the more standard 6 and 8-pin ones, or even the 12-pin one.
If you need custom cables for your build, the number of cables also increases. So, the actual number will depend on what configuration you’re looking for.