MSI said it will support Nvidia’s unsexy-sounding, yet performance-boosting PCIe Resizable BAR feature across many of its AMD and Intel-based motherboards.
Enabling PCIe Resizable BAR is a way to allow the technology underpinning AMD’s new Smart Access Memory feature on Nvidia and Intel hardware, too. Smart Access Memory gives AMD Ryzen 5000 CPUs full access to a Radeon RX 6000-series GPU’s memory, which can deliver varying levels of extra performance, as we found in our Radeon RX 6900 XT testing. Since Smart Access Memory is based on Resizable BAR, activating it on Intel motherboards should offer similar performance benefits, while Nvidia already said Resizable BAR support is coming to GeForce GPUs, which should work with any compatible CPU/motherboard combination.
MSI said it will enable support for GeForce RTX 30-series GPUs on Intel Z590, B560, H510, Z490, B460, H410, Z390, H370, B360, and H310 chipset-based motherboards. Phew.
On the AMD side, MSI said it will enable Resizable BAR on AMD X570, B550, A520, X470 and B450 Ryzen motherboards. MSI will also enable Resizable BAR on its TRX40 Threadripper motherboards. That goes far beyond AMD’s official Smart Access Memory implementation, which is currently limited to 500-series motherboards alone.
The support isn’t automatic. You will need to supply an updated BIOS, and of course, a compatible GeForce RTX 30-series graphics card, which will likely need a VBIOS update of its own. Radeon RX 6000-series GPUs could also see the same performance benefits on MSI motherboards, since they ship with Smart Access Memory active, but MSI is only claiming compatibility with GeForce GPUs for now. AMD would possibly need to ship new drivers to enable full Resizable BAR compatibility on platforms that don’t support Smart Access Memory.
Since MSI will support the technology going all the way back to the 300-series of Intel chipsets, it also means Resizable BAR should work on 8th-gen Intel Coffee Lake CPUs to its newest 11th-gen Rocket Lake CPUs that will release later this quarter.
That may put pressure on AMD to enable its Smart Access Memory on older CPUs and chipsets as well, not just the latest Ryzen 5000 CPUs. MSI’s own guidance said the Resizable BAR feature would only work “with selected AM4” CPUs while there was no such disclaimer for Intel CPUs.
“With the ever-growing size of modern game assets, this results in a lot of transfers. Using Resizable BAR, assets can instead be requested as-needed and sent in full, so the CPU can efficiently access the entire frame buffer. And if multiple requests are made, transfers can occur concurrently, rather than queuing,” the Nvidia blog post said.