Back when AMD announced Smart Access Memory, it was said that only Zen3 processors would support it. Contrary to this, Asus and MSI were able to make it work on systems using AMD 400-series and 500-series motherboards equipped with Zen and Zen2 processors.
Back when AMD said Smart Access Memory would only work with Zen3 processors, there were rumours that older Zen processors couldn’t handle it because they don’t support a special PDEP instruction at native speeds. According to Wccftech, this was then debunked by AMD itself, which said that this wasn’t the case, but the company didn’t share a specific reason for the older Zen processors incapacity.
Despite these claims, Asus has seemingly enabled SAM/Resizeable BAR support on the BIOS of the ASUS B450-PLUS motherboard and it works with a first-gen Ryzen 1700 processor.
As if that wasn’t enough, MSI also shared some screenshots with Wccftech showing X570 motherboards supporting AMD Smart Access Memory on Ryzen 3000 CPUs and Ryzen 4000G APUs. One important thing to note is that both screenshots show an Nvidia GPU was equipped in these systems, meaning they were also supporting Resizeable BAR.
KitGuru says: It takes some tweaking, but it would seem that Smart Access Memory can indeed work on older CPUs, motherboards and even non-AMD GPUs.