https://wccftech.com/msi-x570-b550-a520-motherboards-support-amds-smart-access-memory/

MSI has announced that its entire 500 series motherboard lineup including X570, B550 & A520 products will support AMD's Smart Access Memory feature. The tech is one of the key features supported by AMD's Ryzen 5000 and Radeon RX 6000 series platform, offering a nice boost in gaming performance.

ln conventional Windows-based PCs, processors can only access a fraction of graphics memory (VRAM) at once, limiting system performance. A core aspect of PCI Express technology, the Base Address Register (BAR) defines how much discrete GPU memory space is to be mapped.