You’re starting to build your own computer. You’ve probably read a lot about PCIe and its applications. What exactly is PCIe? What is its purpose? And why is it so highly essential?

In the long run, it would be a sad thought if you did not take advantage of the later-generation PCIe standards to build yourself a high-performance PC. This article will answer the questions above in a straightforward manner, providing you with more information to help you choose the essential components for your PC.

What is PCIe?

PCIe or PCI Express (Peripheral Component Interconnect Express) is a high-speed serial bus standard for PC expansion components. It is intended to replace the older PCI, PCI-X, and AGP bus standards.

In other words, PCIe is a high-speed communication interface standard for expansion components. That is why motherboards always come with various PCIe slots for attaching expansion cards to ensure physical connectivity.

What Are PCIe Lanes?

Physically, PCIe lanes are a set of wires on the motherboard to link data between the extension components and the CPU or chipset. Each lane has 2 pairs of cables for bidirectional data transmission (send/receive data). It makes up the serial bus connection.

Each PCIe slot can have 1 lane, 4 lanes, 8 lanes, or 16 lanes denoted by the letters x1, x4, x8, or x16 respectively. Depending on the design, each motherboard can configure a certain number of PCIe lanes. This depends on:

  1. CPU and chipset to which this motherboard will be paired: CPU and chipset come from two brands, Intel and AMD. Depending on the product series, they are pre-designed with a certain number of PCIe lanes. For example, an 11th generation Intel Core CPU used with the Z590 chipset can connect up to 44 lanes, of which 20 lanes are linked to the CPU and 24 lanes to the chipset.
  2. Support for discrete graphics cards: Usually motherboards have at least one PCIe slot x16 lanes to use for graphics cards. These lanes are usually linked directly to the CPU.
  3. Support for NVMe SSDs: This is a Solid-State Drive with a communication interface via the PCIe bus. You need to distinguish two basic concepts, (1) the communication interface of NVMe SSDs is PCIe, which usually uses x2 lanes or x4 lanes, and (2) the physical connection to the motherboard via M.2 socket rather than PCIe slots.
  4. Expansion cards for other purposes such as storage disk, ethernet, etc. These expansion cards will usually be attached to PCIe slots x1 or x4 lanes.

How Does It Look?

PCIe slots have different sizes depending on the number of lanes arranged on them.

  • PCIe x1: 18 pins, 25 mm long
  • PCIe x4: 32 pins, 39 mm long
  • PCIe x8: 49 pins, 56 mm long
  • PCIe x16: 82 pins, 89 mm long Important Note: The number of PCIe lanes may not match the size of that slot. For example PCIe of the size x16 might have only 8 lanes.

Bandwidth On PCIe Bus

PCIe bandwidth is determined by two factors: generation and number of lanes. The most recent generation is PCIe 6.0, which has been introduced in 2021 (but not on the market yet). The bandwidth of the next generation is almost twice that of the previous generation. And of course, with the most lanes (x16 lanes), the device will achieve the maximum bandwidth of the same generation.

The table below lists the bandwidth of PCIe according to the aforementioned parameters. Note that this is the maximum bandwidth of the PCIe bus, not the speed of the expansion devices.

Recommendation On Your PCIe Lanes and Generations

The generation PCIe 6.0 is not yet available on the market. Meanwhile, the 5.0 generation is not widely used. Intel Core Alder Lake and Intel’s Z690 chipset support PCIe generation 5.0. However, because the application of PCIe 5.0 is limited, motherboards that support this CPU/chipset are not yet widely available.

At the present, you better select a motherboard that supports PCIe 4.0 because the 3.0 generation is gradually becoming obsolete, while the 5.0 generation is not commonly used.

The recommended number of lanes is determined by how you use your PC. There are several cases as follows:

  1. If you use your PC for casual tasks like web browsing, word processing or simple gaming, PCIe doesn’t really make much sense. You can choose a CPU with integrated graphics (GPU built into the CPU) or use discrete graphics cards that take up x8 or x16 lanes. In addition, NVMe SSD with x4 PCIe lanes is enough for data storage needs.
  2. You are a gamer or video editor: You will need at least one graphics card with 16 lanes that link directly to the CPU. NVMe SSD storage drives require 4 PCIe lanes. x1 lane high speed ethernet card.
  3. You are the 3D animation maker: Your PC is better built with a multi-GPU configuration, NVIDIA’s Scalable Link Interface (SLI) or AMD’s Crossfire technology . You can pair 2 to 4 graphics cards in a multi-GPU configuration with each card taking up x8 PCIe lanes. In addition you may need more x4 to x8 lanes for NVMe SSDs.

Applications for PCIe

PCIe is primarily used for graphics tasks due to its high communication speed. They are also used for storage disks and some other peripheral components, as highlighted below.

Graphics Cards

PCIe slots are commonly used for graphics cards. Motherboard manufacturers usually recommend using the top slot for your graphics cards (usually the x16 slot linked directly to the CPU). Graphics cards can come from many different manufacturers, but they use GPUs from either NVIDIA or AMD.

As mentioned, some motherboards can support multi-GPU technology for you to run graphics programs that require high graphics performance. However, you should be aware that these configurations require complex pairing. And make sure that the software you use should be compatible with your SLI (or Crossfire) setup.

NVMe SSDs

If you work in a graphics-related field such as 3D rendering or animation production, you probably know that storing the results of your regular work is essential. That’s to make sure you don’t lose data in the event of a rendering crash or an error in modeling.

With the large size of the model files, it requires very high disk drive access speed. So the combination of NVMe SSD with PCIe high-speed communication interface is a great choice for you.

Ethernet Cards

Most desktops or laptops these days come with an Ethernet port. However, if you need a high-speed Ethernet port for online gaming or for your work, the PCIe Ethernet card is also a good choice.

Other

There are several other functions that are not commonly found on computers, such as video capture, TV, high-quality audio, and so on. These features will be built into the expansion cards and communicate with your computer via the PCIe interface.

In Conclusion

PCIe slots with high-speed communication interfaces provide your PC with a high level of customization, allowing it to be tailored to the various requirements. The choice is yours, and this article can provide you with additional information to help you make the right decision.