Answered: PCI vs. AGP vs. PCIe? Time to Upgrade! (2021)

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!

ELSA GLoria II Pro - AGP Graphic Card

Last Updated: September 10, 2021

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 4.0), on the other hand, can reach up to 32 GB/s when 16 lanes are used.

Don't forget to check out my Recommended PCIe 4.0 CPUs and Motherboards (TR) below.

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.

Even in 2021, there are still a few motherboards available with PCI slots alongside newer ports. However, for any new PC build, you'll probably want to skip this feature.

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 4.0 is the latest version of PCI-Express on the market.

PCIe 4.0 x16 can reach speeds of 32 GB/s.

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

How Fast Is PCIe 4.0?

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PCI-Express (TR) speeds are based on the PCI-Express version and the number of lanes used. One line 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.

The bandwidth for each PCIe 4.0 lane is 2 GB/s. 2 GB/s per lane means that if you use a PCI-Express 4.0 x16 device, it would have up to 32 GB/s of bandwidth available to it.

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

Samsung 980 1TB M.2 SSD Samsung 980 1TB M.2 SSD Check Price on Amazon (affiliate link)

NVMe PCIe add-in cards (TR) 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.

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

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?

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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.

AMD Ryzen 9 5900X AMD Ryzen 9 5900X Check Price on Amazon (affiliate link)

Feel free to jump down to the Recommended PCIe 4.0 CPUs and Motherboards (TR) section below.

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

Which Motherboards Support PCIe 4.0?

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To get full PCIe 4.0 support, you'll need to use a motherboard with the latest chipsets.

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Best AMD High-Frequency CPU: AMD Ryzen 9 5900X

  • Up to 4.8 GHz: perfect for games, video editing, and high-intensity tasks.

  • 12 cores / 24 threads: High core count for the frequency! This combination makes it a great all-around system that can handle almost any job.

  • Check the latest price of the AMD Ryzen 9 5900X on Amazon (affiliate link).

    AMD Ryzen 9 5900X AMD Ryzen 9 5900X Check Price on Amazon (affiliate link)
  • For the AMD Ryzen 9 5900X CPU, you'll need a 5000 series motherboard with the X570 chipset to support PCIe 4.0.

  • Our recommended motherboard to pair with the Ryzen 9 5900X is MSI's MAG X570 TOMAHAWK WIFI Motherboard: MSI MAG X570 TOMAHAWK WIFI MSI MAG X570 TOMAHAWK WIFI Check Price on Amazon (affiliate link)

    • PCIe 4.0 support
    • One 2.5 Gb Ethernet port is faster than most Internet speeds, with room to spare for file transfers.
    • Two NVMe M.2 (TR) slots both run at PCIe 4.0 speeds.
    • Wi-Fi 6 provides great Wi-Fi speeds (not Wi-Fi 6E, but still really good).
    • USB 3.2 Gen 2 offers 10 Gbps USB speeds.
    • Check the latest price of the MSI MAG X570 TOMAHAWK WIFI Motherboard on Amazon (affiliate link).

Best Intel High-Frequency CPU: Intel Core i9-11900K

  • Up to 5.3 GHz: perfect for games, video editing, and high-intensity tasks.

  • 8 cores / 16 threads: Quite a few cores considering the frequency! This combination makes it a great all-around system that can handle almost any task.

  • You'll want to use a good cooler, as the "Thermal Velocity Boost Frequency" feature will improve your clock speed based on how cool you can keep it.

  • Virtualization features make it great for running virtual machines.

  • Check the latest price of the Intel Core i9-11900K on Amazon (affiliate link).

    Intel Core i9-11900K Intel Core i9-11900K Check Price on Amazon (affiliate link)
  • For the Intel Core i9-11900K CPU, you'll need a motherboard with the Z590 chipset to support PCIe 4.0.

  • Our recommended motherboard to pair with the i9-11900K is ASUS's ROG Maximus XIII Hero: ASUS ROG Maximus XIII Hero ASUS ROG Maximus XIII Hero Check Price on Amazon (affiliate link)

    • PCIe 4.0 support
    • Wi-Fi 6E makes it easy to reach the fastest speeds and future-proof your Wi-Fi system.
    • Four NVMe M.2 (TR) slots, which is a lot! (Only two of them run at PCIe 4.0 speeds)
    • Two 2.5 Gb Ethernet ports are faster than most Internet speeds with room to spare for file transfers.
    • USB 3.2 Gen 2x2 offers 20 Gbps USB speeds!
    • Check the latest price of the ASUS ROG Maximus XIII Hero on Amazon (affiliate link).

Best High-Core CPU: AMD Ryzen Threadripper 3990X

  • 64 cores / 128 threads: Insane number of cores/threads.

  • This CPU is going to be best for high-intensity multi-threading such as:

    • 3D graphics rendering (e.g., Blender/3DS Max/Maya)
    • CAD design, simulation, and visualization (e.g., AutoDesk Inventor)
    • Software that does a lot of physics analysis
  • Due to the high price, this CPU is best for business use-cases.

  • Check the latest price of the AMD Ryzen Threadripper 3990X on Amazon (affiliate link).

  • AMD Ryzen Threadripper 3960X (affiliate link) is a backup option if this one isn't in stock and for lower budgets.

    AMD Ryzen Threadripper 3990X AMD Ryzen Threadripper 3990X Check Price on Amazon (affiliate link)
  • For the AMD Ryzen Threadripper 3990X CPU, you'll need a motherboard with the TRX40 chipset to support PCIe 4.0.

  • Our recommended motherboard to pair with the AMD Ryzen Threadripper 3990X is ASUS's ROG Zenith II Extreme Alpha: ASUS ROG Zenith II Extreme Alpha ASUS ROG Zenith II Extreme Alpha Check Price on Amazon (affiliate link)

    • PCIe 4.0 support
    • Five NVMe M.2 (TR) slots all run at PCIe 4.0 seeds, which is insane!
    • One 10 Gb Ethernet port would allow you to transfer a 1 GB video file in under a second!
    • 1 USB 3.2 Gen 2x2 offers 20 Gbps USBs speeds; 9 USB 3.2 Gen 2 ports provide 10 Gbps; 8 USB 3.2 Gen 1 ports provide 5 Gbps; 3 USB 2.0 ports
    • Wi-Fi 6 provides great Wi-Fi speed (not Wi-Fi 6E, but still really good).
    • Bluetooth 5.0 (TR) is great for streaming music to Bluetooth headphones.
    • Check the latest price of the ASUS ROG Zenith II Extreme Alpha on Amazon (affiliate link).

Best Value CPU: Intel Core i5-11600K

  • Half the price of the i9-11900K, but still excellent performance at up to 4.9 GHz.

  • 6 cores / 12 threads: There are a decent number of threads to make it good at everyday multi-threading tasks, such as having tons of browser windows open.

  • Check the latest price of the Intel Core i5-11600K on Amazon (affiliate link).

  • Intel Core i5-11600KF (affiliate link) is a backup option if this one isn't in stock. It is the same other than the lack of integrated graphics support.

    Intel Core i5-11600K Intel Core i5-11600K Check Price on Amazon (affiliate link)
  • For the Intel Core i5-11600K CPU, you'll need a motherboard with the Z590 chipset to support PCIe 4.0.

  • Our recommended motherboard to pair with the i5-11600K is MSI's Z590 PRO WiFi ProSeries motherboard: MSI Z590 PRO WiFi ProSeries MSI Z590 PRO WiFi ProSeries Check Price on Amazon (affiliate link)

    • PCIe 4.0 support
    • Wi-Fi 6E makes it easy to reach the fastest speeds and future-proof your Wi-Fi system.
    • Bluetooth 5.2 (TR) is great for streaming music to Bluetooth headphones.
    • Three NVMe M.2 (TR) slots, which is pretty good! (Only one of them runs at PCIe 4.0 speeds)
    • Two 2.5 Gb Ethernet ports are faster than most Internet speeds with room to spare for file transfers.
    • USB 3.2 Gen 2x2 offers 20 Gbps USB speeds!
    • Check the latest price of the MSI Z590 PRO WiFi ProSeries on Amazon (affiliate link).

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: