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Can I Use a PCIe 3.0 Graphics Card in a PCIe 4.0 Slot?

Learn whether you have to upgrade your PCIe 2.0 or PCIe 3.0 graphics card to work in a newer PCIe 4.0 motherboard slot and how graphics performance could be affected.

NVidia Geforce RTX Graphics Card in a Computer Caspar Camille Rubin / Unsplash

Last Updated: May 17, 2022

Written by Kevin Jones

Newer graphics card prices have been inflated by up to 100% of MSRP over the past year due to various factors, including chip shortages triggered by the pandemic and high demand from crypto miners and holiday shoppers.

However, the prices are now dropping to MSRP for some cards, and the availability of graphics cards is no longer an issue. You can find some Nvidia cards recently in stock in our article on Nvidia graphics card availability.

You may be wondering whether to hold off on buying a new graphics card while you upgrade the rest of your system. If you are considering upgrading, you may be able to save a little by selling your old graphics card.

Let's dig into whether you can keep using your old graphics card in your new system.

Can I Use a PCIe 3.0 Graphics Card in a PCIe 4.0 Motherboard Slot?

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An older PCIe 3.0 graphics card will work in a PCIe 4.0 motherboard slot at PCIe 3.0 speeds. Similarly, an old PCIe 2.0 graphics card will work in a PCIe 4.0 motherboard slot at PCIe 2.0 speeds.

For PCIe 4.0 graphics cards, maximum graphics throughput can only barely exceed that of PCIe 3.0. For this reason, the benefits of upgrading your graphics card to PCIe 4.0 will be minor. However, other differences between PCIe 4.0 and PCIe 3.0 graphics cards could impact performance, unrelated to the PCI-Express version.

PCI-Express versions are backward compatible, meaning that you can use a PCIe 4.0 graphics card or storage device on a PCIe 3.0 or PCIe 2.0 system. However, PCI-Express will use speeds based on the lowest of the two versions for communication. For example, if you use a PCIe 4.0 video card with a PCIe 3.0 system, the video card would be running at PCIe 3.0 speeds.

Reducing the PCIe version would halve the max potential bandwidth. However, you may not experience a performance impact if your device is not using the available bandwidth.

You can refer to the following table to determine the bandwidth limit and decide whether that is adequate for your needs.

PCI-Express Speeds (Rounded)
x1 Bandwidthx2 Bandwidthx4 Bandwidthx8 Bandwidthx16 Bandwidth
PCIe 1.0 250 MB/s 500 MB/s 750 MB/s 2 GB/s 4 GB/s
PCIe 2.0 500 MB/s 1000 MB/s 2 GB/s 4 GB/s 8 GB/s
PCIe 3.0 1 GB/s 2 GB/s 4 GB/s 8 GB/s 16 GB/s
PCIe 4.0 2 GB/s 4 GB/s 8 GB/s 16 GB/s 32 GB/s
PCIe 5.0 4 GB/s 8 GB/s 16 GB/s 32 GB/s 63 GB/s
PCIe 6.0 8 GB/s 16 GB/s 32 GB/s 63 GB/s 126 GB/s

PCIe versions are also forward compatible, meaning that you can use a newer PCIe device with an older system. Similarly, PCI-Express will use speeds based on the lowest of the two versions for communication.

Intel has released their PCIe 5.0 CPUs. Check out Which Intel and AMD CPUs Support PCIe 5.0? and Is PCIe 5.0 Worth It? for details.

CPUs that support PCIe 5.0 also support PCIe 4.0 and PCIe 3.0 devices.

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Is PCIe 4.0 Worth It for Gaming?

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The performance improvement when upgrading graphics to PCIe 4.0 from PCIe 3.0 is currently pretty minor.

It is worth the upgrade to PCIe 4.0 for gaming if you:

  • Want to get every bit of extra performance out of a PCIe 4.0 graphics card
  • Want to future-proof your system
  • Want to free up PCIe lanes for other devices

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

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

Which Desktop Graphics Cards Support PCIe 4.0?

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Both Nvidia and AMD graphics cards supporting PCI-Express 4.0 are available.

All graphics cards with Nvidia's GeForce RTX 30 series GPUs support PCIe 4.0.

All graphics cards with AMD's Radeon RX 5000 and Radeon RX 6000 series GPUs support PCIe 4.0.

ZOTAC Gaming GeForce RTX 3060 Twin Edge OC 12GB ZOTAC Gaming GeForce RTX 3060 Twin Edge OC 12GB Check Price on Amazon Amazon Affiliate Link

List of GPUs That Support PCIe 4.0

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Nvidia GPUs

Nvidia PCIe 4.0 GPUs
Nvidia GeForce RTX 3000 Series

Desktop PCIe 4.0 x16 GPUs
GeForce RTX 3060, RTX 3060 Ti, RTX 3070, RTX 3070 Ti, RTX 3080, RTX 3080 Ti, RTX 3090, RTX 3090 Ti
Nvidia GeForce RTX 3000 Series

Desktop PCIe 4.0 x8 GPUs
GeForce RTX 3050
Nvidia RTX Ax000 Series

Workstation PCIe 4.0 x16 GPUs
RTX A2000, RTX A4000, RTX A5000, RTX A6000
Nvidia GeForce 20 Series

Mobile PCIe 4.0 x4 GPUs
GeForce MX450, MX550, MX570
Nvidia GeForce 30 Series

Mobile PCIe 4.0 x16 GPUs
GeForce RTX 3050, RTX 3050 Ti, RTX 3060, RTX 3070, RTX 3080

Find PCIe 4.0 Nvidia Graphics Cards on Amazon (affiliate link).

AMD GPUs

AMD PCIe 4.0 GPUs
AMD Radeon RX 6000 Series

Desktop PCIe 4.0 x16 GPUs
Radeon RX 6700 XT, RX 6750 XT, RX 6800, RX 6800 XT, RX 6900 XT, RX 6950 XT
AMD Radeon RX 6000 Series

Desktop PCIe 4.0 x8 GPUs
Radeon RX 6600, RX 6600 XT, 6650 XT
AMD Radeon RX 6000 Series

Desktop PCIe 4.0 x4 GPUs
Radeon RX 6400, RX 6500 XT
AMD Radeon RX 5000 Series

Desktop PCIe 4.0 x16 GPUs
Radeon RX 5600, RX 5600 XT, RX 5700, RX 5700 XT, RX 5700 XT 50th Anniv. Ed.
AMD Radeon RX 5000 Series

Desktop PCIe 4.0 x8 GPUs
Radeon RX 5300, RX 5300 XT, RX 5500, RX 5500 XT
AMD Radeon Pro 5000M Series

Mobile Workstation PCIe 4.0 x16 GPUs
Radeon Pro 5300M, Pro 5500M, Pro 5600M
AMD Instinct Series

Server PCIe 4.0 x16 GPUs
Radeon Instinct MI60, AMD Instinct MI100, AMD Instinct MI250, AMD Instinct MI250X

Find PCIe 4.0 AMD Graphics Cards on Amazon (affiliate link).

Multiple PCIe Versions for CPU/Motherboard

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Some CPUs and motherboards provide PCI-Express lanes at multiple PCIe versions. In these cases, you can choose which devices need the most bandwidth to decide which should be connected to the highest version PCIe lanes. While laying out your system, keep in mind that PCIe speeds will be based on the lowest PCIe version between the slot/port and the device.

Can I Use an x4 or x8 Card in an x16 PCIe Slot?

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You can use PCIe cards of a lower lane width (e.g., x2, x4, or x8) in a higher lane width slot (e.g., x16).

PCI-Express will negotiate how many lanes will be used, and your card will work at its full speed, assuming the PCIe slot has the same or higher PCIe version.

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: