PCI is a bus standard designed to connect peripherals to a computer’s motherboard, such as video cards and SSDs. You may also find other references to it, such as “interface”, “slot” or “socket”.
Created in 1993, PCI was designed to replace some previous standards, such as AGP, VESA and USB – before, the interface was used directly on the motherboard. However, conventional PCI has now been left aside, making way for the seventh generation of PCI Express, PCIe 7.0, scheduled for release in 2025.
PCIe 7.0 is advertised as being four times faster than PCIe 5.0. PCIe 5.0 CPUs are available from Intel and AMD, and PCI Express is managed by a company called PCI-SIG. It develops, regulates, and standardizes the bus for the entire industry. Learn more about PCI and how it works below.
What is a bus?
It is the physical and logical interface through which a peripheral communicates with the rest of the system. If your PC has a dedicated video card, for example, there is a high probability that it is connected to a PCIe slot. The bus is also used for other types of cards and resources, such as network cards, sound cards, SSD drives, capture cards, etc.
It may seem strange, but buses are not restricted to desktop computers. Notebooks also have PCIe interfaces, but with a different physical configuration due to obvious space limitations.
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How important is PCIe?
PCIe began in 2004 as an Intel initiative to replace conventional PCI and AGP, standardizing the interface for consumers and manufacturers. There was a time when a good motherboard needed space for several types of buses, and PCIe eliminated that problem.
Because it is a widespread standard, it is important when choosing a new motherboard; a greater number of slots and greater amount of bandwidth available for each of them are important points for intense users.
Those who want to build a high-performance computer and consider multiple video cards in parallel need to be aware of the number of slots the motherboard offers, in addition to the bandwidth available for each of them.
Another important point of PCIe is compatibility, since new devices can be connected to older buses, and older devices can be used with newer versions of the bus.
The issue with this that needs to be taken into account is that older buses offer lower bandwidth limits than current ones. For example, hardware designed for first-generation PCIe has a lower data transfer limit.
This is because the main use of PCIe is to connect video cards to your system. When used in games, video cards generate a large amount of data that needs to reach the processor quickly, for example. To do this, lanes need to connect the two units.
PCIe Generations
PCI-E 1.0 PCI-E 2.0 PCI-E 3.0 PCI-E 4.0 PCI-E 5.0 PCI-E 6.0
Motherboards with PCIe 5.0 support have been on the market for a while now, and Intel’s 12th and 13th Gen Core CPUs support PCIe 5.0 for CPU lanes (i.e. one x16 or two PCIe x8 slots) and PCIe 4.0/3.0 speeds for the remaining lanes. AMD’s Zen 4-based Ryzen 7000 desktop CPUs were the first to support PCIe 5.0.
In some cases, PCIe versions such as 3.0, 4.0, and 5.0 are informally referred to as PCIe Gen 3, PCIe Gen 4, and PCIe Gen 5. The nomenclature is based on the fact that they are the third, fourth, and fifth generations of PCI-Express.
The PCI standard generations last about three or four years. The first arrived in 2004, and the second in 20047. In 2011, we had the debut of the third, and the fourth generation arrived in 2019, being the slowest to launch, due to the difficulties encountered by PCI-SIG in achieving the goal of doubling speeds.
PCIe 5.0 arrived in 2021, just a year and a half after the previous one, and is treated as “an expansion” of the fourth generation, despite also meeting the goal of doubling speeds.
