How Do I Enable Resizable Bar Support On My EVGA Motherboard?

Last Update: 2021/01/29 16:26

Several EVGA motherboards currently feature Resizable BAR support, which will be utilized in current and future graphics cards to increase performance.  However, there are several hardware requirements and additional steps to complete before your system is Resizable BAR-ready.


  1. A graphics card that supports Resizable BAR.  If your graphics card does not have Resizable BAR support, you will not see a benefit when enabling this setting.  Depending on your graphics card's make and model, you may require a driver and/or firmware update.
  2. A motherboard with Resizable BAR support enabled within the motherboard BIOS.  Currently, EVGA Z590, Z490, W999, X299, and Z390 motherboards have resizable BAR support when updated to a current BIOS.  Please visit our Download Center to locate the latest BIOS for your motherboard.

How to Enable Resizable BAR Support in EVGA Motherboards:

For compatible EVGA motherboards, you must enable the "Above 4G Decoding" and "Re-Size BAR Support" settings, and disable "CSM Support".  A full walkthrough of how to change these settings can be found below.
  • Note 1: The CSM Support option is available only if your Windows installation is configured for UEFI.  If the motherboard Boot mode select must be set to Legacy, then you will be unable to enable Resizable Bar support.  Although a full walkthrough of installing Windows in UEFI mode is outside the scope of this FAQ, here are a couple Microsoft documents that discuss the issue in more detail, along with a way to convert your hard drive from a legacy install to a UEFI install:
  • Note 2: Changing your CSM Support setting can affect your ability to boot into Windows.  The Compatibility Support Module is designed to allow you to use the benefits of UEFI with hardware that may not be UEFI compatible.  Disabling the CSM is necessary for Resizable Bar support, but you may find that older hardware may not be compatible with CSM disabled.  Although a full discussion on this topic is outside the scope of this FAQ, you may be able to resolve the issue through simple troubleshooting, such as a firmware update to the legacy device, or you may determine that your legacy device is simply outdated; it may be time to find a newer product with UEFI support.
  1. Enable "Above 4G Decoding" and "Re-Size BAR support"

First, go into the Advanced menu and go into the PCIe Configuration menu:  

At the top, you'll see these options.  The default setting for Above 4G Decoding and Re-Size BAR Support is "Disabled".  Change this to "Enabled" for both settings. Here's before:

and after:
  1. Disable "CSM Support"

Go into the Boot menu.  Make sure your "Boot mode select" is "UEFI".  If you normally boot into Windows using "Legacy" mode, please see Note 1 above, as you will be unable to properly enable Resizable Bar support.  If the Boot mode is instead set to UEFI, you should see a menu further down called "CSM Configuration". 

Enter this menu, and set "CSM Support" to "Disabled". Here's before:

and after:

  1. Save and Exit

After enabling Above 4G Decoding and Re-Size BAR Support, and disabling CSM Support, go ahead and move the Save and Exit menu and...Save and Exit.  Your system will reboot and should boot into Windows.  If you have met the requirements and followed these steps, your system will be Resizable BAR-ready.


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