Screenshots show that Smart Access Memory may also work on older AMD Ryzen CPUs. For the time being it was assumed that this function would only be supported on AMD’s current Ryzen 5000 chips, which are based on the Zen 3 architecture.
According to previous rumors, the original Zen and Zen 2 architectures would not receive support for Smart Access Memory, also known as Resizable BAR. This was because it was thought that SAM depended on so-called pdep instructions. Zen and Zen 2 don’t offer hardware acceleration for that, which results in high latency when those instructions are executed. However, AMD has since debunked the fact that Smart Access Memory is dependent on pdep. The company does this opposite Ian Cutress from Anandtech. With that, the function could still be supported on older Ryzen chips.
MSI would have confirmed this by now. Wccftech recently shared two screenshots showing that Smart Access Memory works on Zen 2 CPUs and an MSI X570 Unify motherboard. The images show CPU-Z listings of a Ryzen 7 3700X CPU and a Ryzen 7 4700G APU, both of which support SAM. This can be seen in the device manager, where a label called ‘Large Memory Range’ is shown. That label only appears when Smart Access Memory is enabled.
Wccftech claims the two screenshots are from MSI itself, although that company has not yet made any information public. That company recently shared a similar screenshot in another press release about Smart Access Memory, in which it also published details of an unannounced Intel Rocket Lake desktop processor. That press release was later removed.
MSI screenshots show Smart Access Memory support on AMD Zen 2 CPUs. Images via Wccftech
A week ago, Reddit user Merich98 already shared a photo showing Smart Access Memory enabled on an ASUS B450 Plus motherboard with bios version 2409 and a Ryzen 7 1700 CPU, Wccftech also writes. That comment has since been removed, but the bios version in question is on ASUS’s website and indeed adds Resizable BAR support to the motherboard. However, it has not been tested whether the function works properly in combination with the Ryzen 7 1700. No motherboards with AMD 300-series chipsets have been detected that support the function.
Smart Access Memory allows CPUs to claim all the available memory of a video card in one go. AMD first introduced that feature with its Ryzen 5000 CPUs and claims performance improvements of up to 11 percent in select games. Smart Access Memory is also the marketing name that AMD uses for this functionality. The function is also known as Resizable BAR and has been incorporated in the PCIe standard for years. In the meantime, various manufacturers have also added the function to Intel motherboards and Nvidia video cards will probably also receive support for Resizable BAR in the long term, although it is not yet clear which GPUs that exactly are.
Smart Access Memory enabled on an ASUS B450-Plus with Ryzen 7 1700. Image by u / Merich98 via Wccftech