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What Is Resizable BAR and How Do I Enable It?

Content Type: Product Information & Documentation   |   Article ID: 000090831   |   Last Reviewed: 12/19/2024
Description Resolution

Description

What is resizable bar? How do I enable it for my system?

Resolution

Resizable BAR (Base Address Register) is a PCIe capability. This is a mechanism that allows the PCIe device, such as a discrete graphics card, to negotiate the BAR size to optimize system resources. Enabling this functionality can result in a performance improvement.

To enable Resizable BAR:

  1. Enter the system’s BIOS/UEFI firmware configuration menu by pressing the DEL key during system start up. This key may vary between each system manufacturer, please check with your system manufacturer for specific instructions as necessary.
  2. Compatibility Support Module (CSM) or Legacy Mode must be disabled and UEFI boot mode must be Enabled.
  3. Ensure the following settings are set to Enabled (or Auto if the Enabled option is not present):
    • Above 4G Decoding
    • Re-Size BAR Support
  4. Use the Intel® Driver and Support Assistant (Intel DSA) to confirm that Resizable BAR is enabled on your system. 

The Resizable BAR option may be described as Re-Size BAR, Smart Access Memory, or Clever Access Memory. Contact the system manufacturer for specific details.

Use your system’s latest motherboard firmware supporting Resizable BAR.

Refer to your system manufacturer's support page for further details.

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