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Answered: PCI vs. AGP vs. PCIe? Time to Upgrade! (2023)

Wondering what the difference is between PCI-Express, PCI, and AGP? If you're still using a computer with a PCI or AGP slot, it's likely time to upgrade your PC!

Answered: PCI vs. AGP vs. PCIe? Time to Upgrade! (2023)

Last Updated: March 18, 2023

Written by Kevin Jones

PCI vs. AGP vs. PCI-Express

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PCI-Express is currently the dominant bus for connecting expansion cards and devices (alongside USB, which is used for externally connected devices). AGP and PCI are typically no longer relevant due to their slow throughput rates of 2133 MB/s and 533 MB/s, respectively. The modern PCI-Express bus (version 5.0), on the other hand, can reach up to 63 GB/s when 16 lanes are used.

Check out the complete list of CPUs supporting PCIe 5.0 in Which Intel and AMD CPUs Support PCIe 5.0?

What Is PCI?

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PCI stands for Peripheral Component Interconnect. PCI is a computer bus used for attaching devices to a computer via expansion boards.

After PCI was introduced in 1992, computer owners could use PCI slots on a motherboard for attaching numerous types of expansion boards. PCI expansion boards include graphics cards, sound cards, modems, TV tuners, additional USB ports, and hard drive adapters.

When PCI was introduced, it replaced various other slots on a motherboard, such as ISA and VESA Local Bus (VLB).

PCI can reach a throughput of 533 MB/s.

PCI is generally no longer found on most motherboards as PCI-Express has replaced it.

What Is AGP?

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AGP stands for Accelerated Graphics Port. An AGP slot on a PC's motherboard is used for connecting a graphics card to the PC. AGP was introduced in 1997 as a replacement for the slower PCI (Peripheral Component Interconnect) bus.

Rather than sharing the bandwidth of the PCI bus with other devices, AGP provides a dedicated bus for the video card. AGP had double the bandwidth compared to PCI and could read textures directly from system memory, unlike PCI, which had to copy the textures.

AGP had a throughput of up to 2133 MB/s, compared to PCI's 533 MB/s maximum.

Starting in 2004, PCI-Express began replacing AGP and PCI.

What Is PCI-Express?

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PCI-Express (PCIe) is an electrical bus used in nearly all modern consumer and server PCs. PCIe slots on desktop PCs allow for connecting various expansion boards, including graphics cards, sound cards, video capture cards, network/Wi-Fi cards, storage devices, and more. PCI-Express is the successor of PCI.

PCIe 5.0 is the latest version of PCI-Express on the market.

PCIe 5.0 x16 can reach speeds of 63 GB/s.

Four PCIe Slots + One PCI Slot on a Motherboard Snickerdo / Wikimedia

How Fast Is PCIe?

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PCI-Express speeds are based on the PCI-Express version and the number of lanes used. One lane is referred to as x1, two lanes as x2, etc. PCI-Express technically supports up to a width of x32. However, most consumer motherboards have some set of these PCIe widths: x1, x2, x4, x8, x16.

PCI-Express Speeds (Rounded)
PCIe 4.0 PCIe 5.0
x1 Bandwidth 2 GB/s 4 GB/s
x2 Bandwidth 4 GB/s 8 GB/s
x4 Bandwidth 8 GB/s 16 GB/s
x8 Bandwidth 16 GB/s 32 GB/s
x16 Bandwidth 32 GB/s 63 GB/s

Intel's 12th generation CPUs currently provide PCIe 5.0 support for CPU lanes (i.e., one x16 or two x8 PCIe slots) and PCIe 4.0/3.0 speeds for the remaining lanes.

The bandwidth for each PCIe 5.0 lane is 4 GB/s. 4 GB/s per lane means that if you use a PCI-Express 5.0 x16 device, it would have up to 64 GB/s of bandwidth available to it.

NVMe M.2 SSD cards use 2 or 4 lanes, which means they have 4–8 GB/s available to them with PCIe 4.0.

Photo of the Samsung 980 1 TB M.2 SSD Samsung 980 1 TB M.2 SSD Check Price on Amazon Amazon Affiliate Link

NVMe PCIe add-in cards can use up to 16 lanes in an x16 slot, thus having up to 32 GB/s of bandwidth available to them with PCIe 4.0.

In comparison, PCIe 3.0 has half of the bandwidth of PCIe 4.0.

PCI-Express 3.0 Speed (Rounded)
x1 Bandwidth 1 GB/s
x2 Bandwidth 2 GB/s
x4 Bandwidth 4 GB/s
x8 Bandwidth 8 GB/s
x16 Bandwidth 16 GB/s

Which CPUs Support PCIe 4.0 and PCIe 5.0?

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PCIe 5.0

Intel's 12th and 13th generation Core processors, code-named "Alder Lake" and "Raptor Lake," support PCIe 5.0. Intel 12th and 13th Gen Core CPUs use an LGA 1700 socket.

AMD Ryzen 7000 processors, released in Q4 2022, also support PCIe 5.0. AMD Ryzen 7000 CPUs use an AM5 socket.

Check out the complete list of CPUs supporting PCIe 5.0 in Which Intel and AMD CPUs Support PCIe 5.0?

PCIe 4.0

Most of AMD's Ryzen 3000 and 5000 series, Ryzen Threadripper 3000 series, and Ryzen Threadripper Pro 3000 series processors support PCIe 4.0. Intel's 11th generation processors, code-named "Rocket Lake," support PCIe 4.0.

Photo of the AMD Ryzen 9 5900X AMD Ryzen 9 5900X Check Price on Amazon Amazon Affiliate Link

Check out the complete list of CPUs supporting PCIe 4.0 in Which Intel and AMD CPUs Support PCIe 4.0?

Other Considerations When Building a PC

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Want to brush up on other new technologies to consider when building a computer? Check out these articles:

Learn More About PCI-Express

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Want to brush up on the latest PCIe products, versions, and features? Check out the articles in this PCI-Express series:

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