AMD Smart Access Memory for older Ryzen CPUs
At launch AMD Smart Access Memory only worked on Ryzen 5000 and Radeon 6000 series
There have been rumors that Ryzen processors prior to Zen3 do not support a special PDEP instruction at a native speed, which would affect the performance of the Resizeable BAR feature also known as AMD Smart Access Memory. If that was true then Ryzen 1000 to Ryzen 3000 processors would probably not receive SAM support, simply because it would not provide the desired performance boost.
The rumor was quickly debunked by Anandtech’s Ian Curtress, who received a message from AMD that this is not the case. AMD Smart Access Memory does not rely on PDEP instruction, meaning that it will work regardless of how well the instruction is supported on the CPU.
Wccftech has published two articles covering the SAM support on various AMD Ryzen CPU series that do not have Zen3 architecture. According to the screenshots published by the website, even the AMD Ryzen 4000G series codenamed Renoir will support SAM on a 500-series motherboard.
AMD Ryzen 4000G “Renoir” AMD Smart Access Memory on MSI X570 UNIFY, Source: Wccftech
The support is also coming to Ryzen 3000 “Matisse” CPUs which are based on Zen2 architecture:
AMD Ryzen 3000 “Matisse” AMD Smart Access Memory on MSI X570 UNIFY, Source: Wccftech
ASUS confirms that even the first generation of Ryzen CPUs will have the ReSize BAR feature enabled, in this case on PRIME B450-PLUS motherboard:
AMD Ryzen 1000 AMD Smart Access Memory on ASUS B450-PLUS, Source: Wccftech
Resizable BAR for NVIDIA GPUs
Earlier this week a story at Igors’LAB has been published that NVIDIA is indeed also working on an alternative to AMD SAM technology. Igor claims that there are discussions going internally on ‘whether and when’ should the GeForce RTX 30 series support the technology. He did not confirm if any final decisions have been made, but ever since the company confirmed it is evaluating the possibility of enabling such technology, it would have been a marketing disaster if Resize BAR would not work on NVIDIA GPUs at some point.
Meanwhile, AMD has not made any public statements in regard to potential SAM support on older Radeon GPUs.