MSI has announced that it has updated the BIOS on AM4 motherboards to support the Re-Size BAR (resizable BAR) feature on Nvidia graphics cards by providing AGESA COMBO PI V2 1.2.0.0.

Currently, this feature is better known as AMD's Smart Access Memory and has already delivered a small but valuable performance boost on compatible Ryzen 5000 processors and Radeon RX 6000 GPUs. Part of the PCIe specification, this feature which is part of the PCIe specification, essentially allows the CPU to freely access the GPU's frame buffer, improving performance.

Nvidia announced at CES 2021 that Re-Size BAR will be included on their graphics cards, highlighting the potential for this feature to improve performance in games. The feature will be available on the RTX 3060 12GB graphics card when it launches in late February, and will be available on the rest of the RTX 30 series in a vBIOS update around March.

In preparation, MSI will offer optimized Re-size BAR functionality on most AM4 motherboards in January: including X570, B550, A520, X470 MAX, and B450 Max boards.

If you are using X470 and B450 motherboards, you will need to wait a little longer for the beta version of the BIOS to be released in February.

In any case, this is ahead of the vBIOS update required by Nvidia.

Asus has already tentatively released a beta BIOS for some AM4 motherboards that are compatible with AGESA V2 PI 1.2.0.0, such as this ROG STRIX B450-E GAMING. It is also likely that the same optimizations will be provided as the corresponding MSI update, but as yet unspecified, the mileage may vary.

MSI and its Mobo manufacturing peers also provide Re-Size BAR support for Intel chipsets, with sporadic support for various Intel generations dating back to the 300 series Coffee Lake chipsets.

However, Re-Size BAR support is not automatically applied, and whether it is turned on depends on the motherboard manufacturer. For a broad overview of what to look out for, see our article on AMD Smart Access Memory Benchmarks and Performance. It will also give you a rough idea of what to expect from this new feature.