PCI Express, or PCIe, has long been the industry standard for connecting peripheral devices to a desktop. In 2021, new PC parts will almost certainly support the present generation (i.e., PCIe 4.0). However, Intel’s next generation of CPUs, Alder Lake, which is expected to be released later this year, will shift us to the fifth generation. The new generation is bound to provide substantially quicker data transfers.

Announced in 2017 with basic specs, the PCIe 5.0 standard was formally certified by the PCI Special Interest Group in 2019. The standard isn’t anticipated to make its way into PCs until late 2021, when Intel adds PCIe 5.0 compatibility to its next CPUs and motherboards. 

What is PCIe? 

The peripheral component interconnect express, abbreviated as PCIe, is a standard for connecting multiple components in a desktop computer. It’s a crucial interface standard on a contemporary computer, since it allows different components to interact with one another.

It allows you to connect your CPU to graphics cards, solid-state drives (SSDs), and wireless networking devices. In the case of a desktop PC, you’ll need PCIe slots on your board to connect multiple cards, and the kind and number of slots available may differ depending on the board you choose.

PCIe slots and cards are frequently denoted by a numerical value followed by an x (e.g., PCIe x1, x2, and x4). The value represents the number of lanes available in the PCIe slot. PCIe x1 refers to a single lane, whereas PCIe x16 refers to 16 lanes. The greater the number is, the faster data can move. The highest configuration available is x32. 

A PCIe x4 slot, having four lanes, can transfer data at four bits per cycle, whereas a PCIe x16 slot with 16 lanes offers a rate of 16 bits per cycle. However, regardless of the number of lanes each component indicates, cards and slots can be combined and matched, with the slower part determining data bandwidth. A PCIe x2 card, for example, can be connected to a PCIe x4 slot on a motherboard. Since the card has two lanes, it will limit your bandwidth. In contrast, if a PCIe x8 card is placed into a PCIe x4 slot, data will only flow at half the speed of a card inserted into a PCIe x8 slot.

The PCIe x16 slot is the magical number for gamers, and most GPUs of today require a PCIe x16 slot to properly utilize the card’s potential. Even though PCIe x32 is available, it is costly and uncommon, and most PC components are limited to x16.

Present Generations

There are four generations presently in use (i.e., PCIe 1.0, PCIe 2.0, PCIe 3.0 and PCIe 4.0). With each generation, the bandwidth doubles. 

How can you know what kind of performance a PCIe expansion card will provide? Your PCIe card will operate at the lowest generation currently available. You’ll get PCIe 2.0 performance if you install a PCIe 2.0 card in a PCIe 3.0 slot.

Future Generations

PCIe 5.0

PCIe 5.0 was released as an official standard early in May. The throughput is projected to be 128 Gbps. It is designed to support interoperability with earlier PCIe versions and features electrical modifications to increase network integrity. The first PCIe 5.0 devices will most probably hit the market in 2022 for business clients, with consumer versions following soon after.

PCIe 4.0 and PCIe 5.0 are expected to coexist for a time, with PCIe 5.0 being utilized for high productivity and performance demands, such as networking applications and GPUs for AI operations.  As a result, PCIe 5.0 will primarily be utilized in data centers and intensive environments, while PCIe 4.0 will suffice for less-intensive workloads.

PCIe 6.0

The standards for PCIe 6.0 will most likely be released in 2021. We won’t see products until the end of 2022, if not later in 2023.

PCIe 6.0 will provide twice the bandwidth of PCIe 5.0, which will be 256 GB/s over the same number of lanes as PCIe 5.0. The data transmission rate will increase to 64 GT/s, up from 32 GT/s in PCIe 5.0. Backward compatibility with earlier PCIe versions is also planned with PCIe 6.0.

PCIe 4.0 vs. PCIe 5.0

Each PCIe generation differs mostly in terms of speed. PCIe 1.0 featured an 8 GB/s bandwidth and a 2.5 GT/s rate clocked at 2.5 GHz. The PCIe 4.0 standard, which is included in many recent AMD and Intel CPUs, allows for bandwidth of up to 64 GB/s and a giga transfer rate of up to 16 GT/s at a frequency of 16 GHz.

With double bandwidth, giga transfer and frequency, PCIe 5.0 is a PCIe 4.0 expansion, allowing for much quicker data transfer. A 32 GT/s rate, a bandwidth of up to 128 GB/s, and a 32GHz frequency are all on the table.

The main distinction between a giga transfer (GT/s) rate and bandwidth (GB/s) is that a giga transfer rate indicates raw speed, whereas bandwidth is a rate of data transfer. Raw speed shows the number of bits transmitted each second, and the data transmission rate accounts for overhead. A PCIe 5.0 x8 link, for example, provides 32 GT/s of raw speed but only a 31.5 GB/s bandwidth.

You need to wait until late 2021 to be able to use PCIe 5.0 in your next desktop setup, as that’s when Intel plans to introduce its Alder Lake CPU family, which will be available for both mobile and desktop use. Intel is the only firm that has announced support for the new standard thus far.

According to recent reports, Alder Lake will require a new socket and motherboard, and gamers would need to purchase a new board to benefit from all of the new features, including PCIe 5 compatibility. The series will come with architectural improvements, a move to 10nm Super Fin production, PCIe 5 compatibility, and ultrafast DDR5 memory, which will altogether offer a 2x performance boost in multithread computing. 

Because high speeds increase the risk of signal loss, the new standard includes features to better counter the risk than PCIe 4.0, ensuring data safety.

Is an upgrade really needed?

The higher transfer speeds are ideal for data centers, artificial intelligence applications, and heavy workloads. The higher speeds will allow AI applications to analyze more data at a faster rate. The shift to PCIe 5.0 could be highly beneficial for some businesses, such as cryptocurrency mining. However, home users are much better off with the speeds delivered by PCIe 4, or even the previous PCIe 3.0. 

According to our PCIe 4.0 vs. PCIe 3.0 analysis, even the most powerful graphics cards, such as the Nvidia GeForce RTX 2080 Ti, are unable to fully utilize the bandwidth provided by a PCIe 3.0 x16 slot. That said, PCIe 5 will be too much. Nevertheless, the new version will better support NVMe storage devices and RAID setups.

With higher speeds, devices that connect to a PCIe slot, such as graphics cards, should require a smaller number of lanes in the future. Instead of the x16 lanes required by the current PCIe 4.0 standard, we may lower the demand to just x8 lanes with PCIe 5.0. With fewer lane requirements to reach equivalent speeds, gamers may be able to create systems that are just as powerful in a smaller, more compact form factor.