AMD Ryzen 3000 and Older Zen Chips Don’t Support SAM Due to

AMD Ryzen 3000 “Matisse” processors based mostly on the “Zen 2” microarchitecture, in addition to older AMD processors based mostly on “Zen+” and “Zen” microarchitectures, don’t assist the corporate’s Smart Access Memory (SAM) function being launched with Radeon RX 6000 collection graphics playing cards. SAM is actually a branding of the Resizable Base-Address Register (Resizable-BAR) function developed by the PCI-SIG; which permits a processor to see a graphics card’s total video reminiscence as a single addressable block, moderately than by way of 256-megabyte apertures. Apparently the PCI-Express root advanced of Ryzen 5000 “Vermeer” processors introduce a PCIe physical-layer function referred to as full-rate _pdep_u32/64, which is required for resizable-BAR to work.

It will get extra fascinating—Intel processors have been supporting this function for the reason that firm’s 4th Gen Core “Haswell,” which launched it with its 20-lane PCI-Express gen 3.zero root-complex. This implies that each Intel processor relationship again to 2014 can technically assist Resizable-BAR, and it is only a matter of motherboard distributors releasing UEFI firmware updates for his or her merchandise (i.e. Intel 8-series chipsets and later). AMD extensively advertises SAM as including a 1-2% efficiency enhance to Radeon RX 6800 collection graphics playing cards. Since this can be a PCI-SIG function, NVIDIA plans so as to add assist for it on a few of its GPUs, too. Meanwhile, along with AMD 500-series chipsets, even sure Intel 400-series chipset motherboards began receiving Resizable BAR assist by way of firmware updates.