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

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.

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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 Bandwidth	x2 Bandwidth	x4 Bandwidth	x8 Bandwidth	x16 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.

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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?.

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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.

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 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).

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.

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.

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

• Cases:
  • How to Choose the Best PC Case
• CPUs:
  • Which Intel and AMD CPUs Support PCIe 5.0?
  • Which Intel and AMD CPUs Support PCIe 4.0?
  • LGA 1700 CPU List
  • LGA 1200 CPU List
  • Look up an Intel or AMD CPU on TechReviewer for related recommendations:
• CPU Coolers:
  • What is the Best Type of CPU cooler for a Gaming PC?
  • How to Choose a CPU Cooler for Your PC
  • Best LGA 1700 CPU Cooler for Intel's 12th Gen Core Processors
  • Best AM4 CPU Cooler for AMD Processors
• Storage:
  • Can an SSD Improve PC Gaming Performance? and Does an SSD Increase FPS for PC Gaming?
  • Storage Type Comparison: M.2, U.2, NVMe, SATA, SSDs, HDDs
• Memory:
  • How to Choose the Best RAM for Your PC
  • How Much RAM Do You Need for Gaming? and Is 32 GB of RAM Worth It for Gaming?
  • DDR4 vs. DDR5? Which You Should Buy
  • Is DDR5 Worth It? The Benefits of DDR5 and What Is DDR5?
  • Which Intel and AMD CPUs Support DDR5?
• PCI-Express:
  • Is PCIe 5.0 Worth It?
• Motherboards:
  • Which Motherboards Support PCIe 5.0?
  • Which Motherboards Support PCIe 4.0?
  • Which Motherboard Should You Buy for Intel's 12th Gen CPUs?
• Graphics Cards:
  • Which Graphics Cards Support PCIe 4.0?
• Power Supplies:
  • How to Choose the Best Power Supply for a Gaming PC
  • How to Choose a PC Power Supply
• Keyboards:
  • Best Mechanical Keyboard for Gaming
• Monitors:
  • How to Choose a Gaming Monitor

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

• What is PCIe?, What is PCIe 5.0?, and What is PCIe 4.0?
• Is PCIe 5.0 Worth It? and Is PCIe 4.0 Worth It?
• Which Intel and AMD CPUs Support PCIe 5.0?
• Which Intel and AMD CPUs Support PCIe 4.0?
• Which Motherboards Support PCIe 5.0?
• Which Graphics Cards Support PCIe 4.0?
• How Fast is PCIe 5.0? and How Fast is PCIe 4.0?
• Is PCIe Backward Compatible?
• Can I Put a PCIe x4 or x8 Card in an x16 Slot?
• Can I Use a PCIe 4.0 NVMe SSD in a PCIe 3.0 Motherboard Slot?
• Can I Use a PCIe 3.0 NVMe SSD in a PCIe 4.0 Motherboard Slot?
• Can I Use a PCIe 4.0 Graphics Card in a PCIe 3.0 Slot?
• Can I Use a PCIe 3.0 Graphics Card in a PCIe 4.0 Slot?
• What is the Latest Version of PCIe?
• PCI vs. AGP vs. PCIe? Time to Upgrade!