AMD Ryzen 3000 CPUs get go-ahead for performance boosting Smart Access Memory

Smart Access Memory
(Image credit: AMD)

AMD has today made available Smart Access Memory (SAM) on Ryzen 3000 CPUs. The feature, which allows for more effective communication between CPU and GPU, had previously required both the latest Ryzen 5000-series CPU and RX 6000 GPU in order to function, but is now been transplanted to Zen 2 desktop chips.

Smart Access Memory is a feature that uses a native specification of the PCIe specification, Resizable BAR, to allow for greater and more effective communication between CPU and GPU. It essentially opens up the entire graphics card memory to the CPU, as opposed to how it usually functions—divvying up small (roughly 256MB) chunks at a time.

In order to enable Smart Access Memory, you'll now need:

  • An AMD 500-series motherboard
  • Ryzen 5000 or 3000 CPU
  • RX 6000 graphics card

That will also include the new AMD RX 6700 XT graphics card when its release date rolls around later this month on March 18.

All of that gear will need to be updated to the latest versions of drivers and BIOS, too.

Unfortunately, that doesn't include the Ryzen 5 3400G and Ryzen 3 3200G APUs, as AMD clarifies on its website's footnotes.

Then you just dive into said BIOS, turn on 'Above 4G Decoding' and 'Re-Size BAR support' (exact wording may vary), and bingo, some more performance free-of-charge.

I see no reason why you'd not enable it on compatible gaming PCs too. Granted, it's not the biggest performance gain in the world, but it doesn't cost you anything.

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(Image credit: MSI)

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In our testing, SAM nets anything from zero performance gain to 17% across a range of games and resolutions. For the most part, however, you're looking at something like 1–7%. Whether that'll differ with Zen 2 chips, we don't yet know. But I'd guess it'd stay roughly the same.

Adding that capability to Ryzen 3000 CPUs is certainly welcome, especially as Intel and Nvidia have jumped on board and are soon to be offering Re-Size BAR functionality too with compatible cards, CPUs, and motherboards. 

But with AMD's reliance on an RX 6000-series GPU, which are in short supply, still in effect, I feel the effects of SAM will be muted for many for a little while yet.

Jacob Ridley
Senior Hardware Editor

Jacob earned his first byline writing for his own tech blog. From there, he graduated to professionally breaking things as hardware writer at PCGamesN, and would go on to run the team as hardware editor. Since then he's joined PC Gamer's top staff as senior hardware editor, where he spends his days reporting on the latest developments in the technology and gaming industries and testing the newest PC components.