MSI has announced it is updating AM4 motherboard BIOSes with support for Re-Size BAR (resizable BAR) functionality on Nvidia graphics cards, courtesy of AGESA COMBO PI V2 184.108.40.206.
We best know said feature today as AMD's Smart Access Memory, which already offers that small but worthwhile performance increase on compatible Ryzen 5000 processors and Radeon RX 6000 GPUs. Part of the PCIe specification, the function essentially allows a CPU unfettered access to the GPU's frame buffer to improve performance.
Nvidia announced Re-Size BAR was coming to its graphics cards over at CES 2021, citing the possible performance boost the feature can offer in-game. This is set to arrive ready for the RTX 3060 12GB graphics card at launch, sometime in late February, and will be switched on for the remainder of the RTX 30-series with vBIOS updates around March.
In preparation of that, MSI is bringing optimised Re-size BAR functionality with its next major BIOS rollout on most AM4 motherboards in January, including: X570, B550, A520, X470 MAX, and B450 Max boards.
If you're using an X470 and B450 motherboard, you'll have to wait a little longer for a beta version of the BIOS to release in February.
Either way, that's ahead of Nvidia's required vBIOS update.
Asus has already tentatively released a beta BIOS for some of its AM4 motherboards fit with the AGESA V2 PI 220.127.116.11, such as this ROG STRIX B450-E GAMING. That's also likely to deliver the same optimisations as the corresponding MSI update, but mileage may vary as it's not yet specified.
MSI and its mobo manufacturing cohorts are also bringing Re-Size BAR support to Intel chipsets, and we've seen sporadic support for a range of Intel generations all the way back to 300-series Coffee Lake chipsets.
Re-Size BAR support isn't automatically applied, however, and turning it on will vary by motherboard manufacturer. For a rough rundown of what to look out for, check out our AMD Smart Access Memory benchmarking and performance article. That'll also give you a rough idea of what to expect out of the new feature.