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What Are PCIe Slots & Their Uses?

It is not always the processor that decides how powerful your computer is in reality. It is the sum total of the components in the entire motherboard that defines the power of your computer.

Regarding the components of your motherboard, PCIe is the interface for connecting input and output components on the motherboard. Different generations of PCIe are available, and they impact the speed of your machine significantly. We will state everything you need about PCIe slots and their applications.

What is PCIe?

PCIe stands for peripheral component interconnect express. It is a standard for connection between the motherboard and peripherals. The motherboard acts as the host while the peripherals like graphics card, SSD, and expansion cards as the endpoints.

PCIe is the best interface standard for high-speed input and output components connecting to the motherboard. Therefore, high-performance motherboards come with PCIe slots where the peripherals are connected. PCIe offers higher bandwidth and lower latency.

Kinds of PCIe Slots

There are five kinds of PCIe slots available, and they are x1, x2, x4, x8, and x16. All these numbers stand for the number of lanes on the PCIe slots. The lanes are responsible for transferring data. The higher the number of lanes, the faster the data transfer rate. More specifically, a PCIe x4 slot can transfer data four bits per cycle.

  • PCI Express x1 Slot – This is the smallest and used for network adapters and USB cards.
  • PCI Express x4 Slot – This has 4 lanes but can fit into x16 slots. It is used for SSD cards and network adapters.
  • PCI Express x8 Slot – This has 8 lanes but can fit into x16 slots. It is used for GPUs mostly as well as SSD cards.
  • PCI Express x16 Slot – This is the largest and used for high-performance GPUs.

How Does PCIe Slot Work?

The PCIe slot has been the most reliable way to connect video, audio, storage, and network cards. However, the cards have upgraded with time for better performance. That is why PCI have got upgraded to PCI-X with more bandwidth from 32-bit to 64-bit. But PCI-X has a lot of shortcomings, and PCIe overcomes them.

PCIe acts like a network to control serial connections. Every connected device has its own connection instead of all congesting one connection, like a bus connection. Therefore, there is no need to share the bandwidth in PCIe; hence, the data transfer speed is far more and perfect for modern high-performance cards.

Every PCIe slot has two parts called the cards and the lanes. Cards are referred to as mechanical, while lanes are referred to as lanes. If the PCIe slot has x16 mechanical and x8 electrical, you can have 16 cards, but performance gets halved due to half the lanes. That is how you can fit a PCIe x8 slot into an x16 slot though the performance is half the x16 slot from all perspectives.

How Does PCIe Generation Matter In Terms Of Speed?

Different generations of PCIe have different speeds. By speed, we are referring to the rate of data transfer. Every new PCIe generation brings in double the speed of the previous generation. PCIe 1.0 has 2.5 GT/s speed, while PCIe 2.0 has 5 GT/s. Not just the data transfer rate, even the bandwidth doubles with every new generation. However, you should have same generation ports and cards for a better outcome.

Comparison of PCIe Slot Generations

Generation Gigatransfer Frequency Bandwidth
PCIe 1.0 2.5 GT/s 2.5 GHz 8 GB/s
PCIe 2.0 5 GT/s 5 GHz 16 GB/s
PCIe 3.0 8 GT/s 8 GHz 32 GB/s
PCIe 4.0 16 GT/s 16 GHz 64 GB/s
PCIe 5.0 32 GT/s 32 GHz 128 GB/s
PCIe 6.0 64 GT/s 32 GHz 256 GB/s

What Are PCIe Cards and PCIe Lanes?

PCIe cards are expansion cards that are actually hardware like graphics cards that you can add to your computer through PCIe slots. PCIe lanes are pairs of wires that form the link between PCIe devices and the processor or the motherboard chipset. These wires run through the motherboard like a highway where the vehicles are data travelling to and fro simultaneously.

What Cards Can You Plug in PCIe Slots?

Here is the list of the cards that you can fit into PCIe slots.

1. Graphics Cards

Graphics cards are the most widely used cards that are plugged into PCIe slots. Graphics cards are responsible for visuals and they are equipped with processors. Most graphics cards fit into PCIe x16 slots because they need 16 lanes to be fully functional.

2. Sound Cards

Every motherboard comes with built-in sound cards. However, when users have better and higher-end audio needs, a better sound card is something you need. You can install external sound cards only through PCIe slots.

3. Ethernet Network Cards

Most motherboards come with network cards with average speed but if you want a high network speed, you have to install an external network card. That is possible only through a PCIe slot, and you get compatible ethernet network cards or NIC cards.

4. Wireless + Bluetooth Network Cards

Not all computers have a dedicated wireless internet connectivity card. But you can install a wireless network card on your motherboard via PCIe slots. Even if your motherboard has a wireless network card, the speed may be average and you can override it with an external wireless network card.

The same is applicable to Bluetooth network cards as well. Most computers do not have Bluetooth cards built into the motherboard. Even if there is one, it is likely to have an older version of Bluetooth. You can have the latest Bluetooth version by installing an external Bluetooth card into the PCIe slot.

5. Video Capture Cards

If you want to have a dedicated video capture card, you have to install it through a PCIe slot. Video capture cards are popular because of online gamers and video streamers. You can capture high-quality video of gameplay and live streams.

6. SATA Expansion Cards

If you want to expand your storage capacity, you can use a PCIe SATA expansion card is a possibility. You need to consider certain factors before purchasing a SATA expansion card such as the number of SATA slots, the presence of a RAID controller, and likewise. SATA expansion cards are available for PCIe x1 to x 8 slots.

7. M.2 NVMe Expansion Cards

The best way to upgrade storage capacity as well as the overall speed of your system is installing an SSD can do wonders. There are PCIe x4 and x8 slots available to plug in SSD, and SSD happens to be the fastest hard drives till date. Generally, motherboards have a dedicated M.2 slot, but PCIe is always a preferred option.

8. TV Tuner Cards

Just like a video capture card, you need a TV tuner card to receive signals from the TV. In today’s world, TV tuner cards are popular among gamers. You will need a PCIe slot to plug it in and stream video from TV to computer easily.

9. Port Expansion Cards

There are always limited ports built into the motherboard. You may need extra ports like extra USB ports. That is where you need port expansion cards and they can only be installed in PCIe slots.

10. Risers/Splitters

Risers and splitters are very much like port expansion cards and their objective is to add extra ports to the motherboard. PCIe slots add risers and slitters to system if they are required.


PCIe slots are one of the most important components on any motherboard. There are different generations of PCIe slots with different specifications, and we have explained how generations can affect different parameters. Along with that, we have explained the possible applications of PCIe slots. The bottom line is that the PCIe slots and cards can take the performance of your system to the next level with the best hardware set.

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