Is Ryzen 3000 series compatible with SAM, or is that something only implemented in 5000 series? Most of the news only talk about MBs supporting SAM when paired with 5000 series, but as far as I understand it, SAM should be part of the PCIe gen 3 spec, right? Shouldn't that mean that all CPUs with PCIe-3 capabilities have SAM compatibility as well?

Ricardo:

Is Ryzen 3000 series compatible with SAM, or is that something only implemented in 5000 series? Most of the news only talk about MBs supporting SAM when paired with 5000 series, but as far as I understand it, SAM should be part of the PCIe gen 3 spec, right? Shouldn't that mean that all CPUs with PCIe-3 capabilities have SAM compatibility as well?

Part of spec is increased size of memory which can be directly accessed. SAM on Zen3 (according to AMD) does access this increased region much faster (at higher rate) than older generations. Technically, I expect that even older Zen CPUs can benefit to some degree. I would not expect performance gains, but likely similar improvements to frametime variance as Zen3 shows. And that means boost to minimum fps too. But choice is on AMD.

Fox2232:

SAM on Zen3 (according to AMD) does access this increased region much faster (at higher rate) than older generations.

Nobody knows this is for sure, the instruction used is for swizzling, not data movement

Astyanax:

Nobody knows this is for sure, the instruction used is for swizzling, not data movement

I do agree, that's why I wrote "according to AMD". I still expect that feature could be available. And it is not easy to say how good or limited it will be on older generations.