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What Are PCIe Connectors Used For? – Learn Here

You may be wondering, what are PCIe connectors used for? PCIe (Peripheral Component Interconnect Express) cards connect to specific ports on a computer known as PCIe slots. These cards extend the functionality of a computer.

PCIe cards have terminals that make up a PCIe connector. A PCIe connector is what allows the hardware you are attaching to your motherboard to send data between the component and the computer.

A good example can be taken from a graphics card. These devices usually require a PCIe X16 connector to efficiently transmit the high bandwidths of data it produces.

There are several other types of PCIe connectors and they are useful for various other components as you’ll see.

What Are PCIe Connectors Used For?

What are PCIe Connectors
PCIe Connectors

For one electrical component to connect with another one, there needs to be a slot and a connector.

For PCIe cards, connectors need to be standardized for different manufacturers to create devices that work properly with existing motherboards.

Hence, PCIe connectors come in various sizes but follow the same standard across different manufacturers. This offers high interoperability between different devices in the same computer and allows things like backward compatibility.

Here are some uses of PCIe connectors and they are more or less inter related.

Also Read:

Expansion Slots

PCIe are essentially the primary slots used for adding high speed cards like graphics cards, wireless cards, SSD cards, Raid card etc.

They are used to expand the capability of the motherboard and the PC.

They allow high speed data transfer allowing them to house cards that require a lot of bandwidth.

Data Transfer

PCIe devices generate a lot of data when operating. This data will need to be made available to the user or passed to other components for various other purposes like processing or transmission.

To make this possible, PCIe cards use their connectors. Depending on the configuration, you can have an X1, X4, X8, or X16 connector.

These work the same and only have different bandwidths because the channel size differs between them. There’s a further disparity between different generations.

Data transmission through the PCIe bus is very fast which makes it ideal for latency-sensitive applications.

Powering Devices

While you may have been wondering what are PCIe connectors used for, you may not have guessed that they are used for power supply.

Electrical components need to be powered to function. For some components that are connected via PCIe, drawing power from the computer through the PCIe connector is necessary for operation.

A PCIe slot is capable of supplying PCIe devices with power through the PCIe connector. This is, of course, dependent on the PCIe card itself. Some cards with low power needs can get powered through the PCIe.

In other cases, some very demanding units, like high-performance graphics cards, will require a direct power supply from the computer’s PSU.

PCIe Connector Pins

164 connector pins PCIe slot
164 connector pins PCIe slot

In some literature a PCIe connector may be referring to the pins at the back of a PCIe slot. The pins basically allow the PCIe slot to attach to the main board.

You can find PCIe slots with 164, 52 etc connector pin.

Types of PCIe Connectors

What Are PCIe Connectors Used For
source: ccboot.com

To further understand what are PCIe connectors used for, you need to know about the different kinds of PCIe connectors available.

These vary by size which also determines the kinds of slots that the cards can fit in.

X1 Connector

This is the smallest PCIe connector available on any PCIe device. Because of this, a device that uses this can be used on any available PCIe slot.

Various devices use the PCIe X1 connector. It may have a shorter length, hence fewer terminals, however, with the popular PCIe 3.0, an X1 connector will give you speeds of up to 985MB/s.

Devices that use this connector include port expansion cards and M.2 NVME drive slots.

X4 Connector

This connector is used by devices that require more bandwidth than the X1 connector can provide. It is also longer than the X1 connector. This means you can only use it on an X4 and above the slot.

However, you can also connect it to an available and open-ended X1 slot but this should only be done when there’s no other choice since you sacrifice performance this way.

With this, you get speeds of up to 3940MB/s when using a third-generation PCIe. On a fourth-generation interface, you get roughly twice the speed.

X8 Connector

This is meant for devices that require high bandwidth throughputs. The connector uses an X8 or X16 slot on the motherboard and is capable of up to 7880MB/s transfer speeds for third-generation devices and slots.

Fourth-generation devices can transmit up to 15752MB/s via these connectors, making it ideal for demanding components.

These connectors are used by various hardware including network cards and some high-performance NVME expansion cards.

X16 Connector

This is the largest PCI-E connector you can find on most devices. It goes into an X16 slot but will also run in any other slot as long as it fits. A drawback is that with smaller slots you will be sacrificing some of your performance.

The X16 connector is used by the most demanding hardware like graphics cards which generate and output large amounts of data.

For the best performance out of these cards, this connector is used and it delivers speeds of up to 15760MB/s and 31504MB/s for the third and fourth generations of PCIe.

PCIe Generations

pcie speeds
Source: Wikipedia

You have seen PCIe generations a few times now. It’s also important to be familiar with this in the quest to learning what are PCIe connectors used for.

An organization known as PCI-SIG (Peripheral Component Interconnect Special Interest Group) is in charge of laying put the standards used for PCIe connections.

They do this by developing and maintaining a list of requirements that manufacturers follow. PCIe generations are part of that standard and denote the different standards of the PCIe devices depending on when they were developed.

Currently, there are 1 to 6 generations with the latter expected to be available in around 2023.

The point to note here is that speed of each lane doubles with every generational increment.


You now have a better understanding of what are PCIe connectors used for. They provide the interface through which PCIe devices connect with PCIe slots on a computer, facilitating things like data transfers and power supply.

PCIe connectors are developed from standards created by PCI-SIG, and they denote the physical size of the connector, their expected bandwidths, and even the generation of the device.

From these standards, manufacturers build PCIe devices to take advantage of the computer’s resources and provide data to the motherboard and the user.

PCIe devices are high-performance components and they work through these complex connectors.

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