Motherboard · medium

How to fixPCIE-GEN-MISMATCH

PCIe generation - speed mismatch

What this error means

PCIE-GEN-MISMATCH shows up as a medium-severity motherboard fault. GPU or NVMe SSD running on PCIe 3.0 instead of PCIe 4.0/5.0, performance is significantly reduced. Reports of PCIe generation - speed mismatch usually describe a sudden crash, brief unresponsiveness, or a stop-code screen appearing out of nowhere. Work through the steps below in order.

Before you begin

Save open work and back up important files. Note any recent driver or hardware changes. If Windows cannot start, use the startup guide first.

Work through these checks

0 of 3 complete
01Set PCIe slot to Auto or Gen4 in BIOS

Set PCIe slot to Auto or Gen4 in BIOS.

Use the instructions for your exact device and operating system. Check the manufacturer’s documentation before changing firmware, hardware, or system settings.

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02Move the GPU to the primary PCIe x16 slot

Move the GPU to the primary PCIe x16 slot.

Use the instructions for your exact device and operating system. Check the manufacturer’s documentation before changing firmware, hardware, or system settings.

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03Verify GPU speed with GPU-Z Bus Interface tab

Verify GPU speed with GPU-Z Bus Interface tab.

Use the instructions for your exact device and operating system. Check the manufacturer’s documentation before changing firmware, hardware, or system settings.

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Possible causes

  • The CPU or board does not support the higher generation PCIe
  • GPU in secondary slot which is limited to PCIe 3.0 x4
  • Incorrect PCIe settings in BIOS (Gen 1/2/3 instead of Auto)

Useful Windows tools

These commands open Windows tools. Review any action inside the tool before applying changes.

dxdiag