What Is Smart Access Memory (SAM Or Resizable BAR)?


Smart Access Memory is AMD’s alternative to Resizable BAR, delivering a better connection between the GPU and CPU for a solid performance bump.

While NVIDIA and Intel are slowly introducing Resizable BAR on their platforms too.

Back in late 2020, AMD announced their RX 6000 lineup of GPUs that are based on the RDNA 2 architecture. During the presentation, Lisa Su, the CEO of AMD spared a moment to focus on SAM or Smart Access Memory.

Lisa Su claimed that this new feature with RDNA 2 graphics card would provide a performance uplift of 5% to 15%, depending on the game. That’s a solid increase in performance considering that all you have to do is flip a switch.

What exactly does this feature do and why hasn’t been this introduced earlier in the PC industry?

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How Does It Work?

In Layman’s Terms, by enabling Smart Access Memory a better communication stream is created between the processor and the graphics card.

However, this new feature has been properly and fully developed only for the Ryzen 5000 generation of CPUs and RDNA 2 GPUs. So, only if you pair hardware from these latest generations you will be able to utilize SAM. Otherwise, the feature will not be available.

Fortunately, that is not the case anymore. AMD has pushed motherboard BIOS updates, allowing SAM to work with Ryzen 3000 series CPUs too. Of course, it is still limited only to RDNA 2 (RX 6000).

NVIDIA’s has had a say in this too, but we’ll touch on that part of the subject later.

Performance Boost

What Graphics Card Do I Have

The explanation behind SAM is easy to understand, but where does the performance boost come from?

Well, without this new feature, the way CPUs and GPUs communicate is a bit outdated. Previously, the processor could only access a maximum of 256MB of the graphics card’s VRAM. At the time, this was more than enough.

Today’s games are much more demanding and most GPUs come with more than 6GB of VRAM, it was logical to try and improve the processor’s access to the VRAM.

In other words, a better and more efficient connection between these two essential PC parts was a must.

By bypassing all of the bottlenecks, the Ryzen chip can now easily access the memory of RDNA 2 graphics cards.

Based on AMD’s claims, SAM can deliver a performance boost of around 10% in games such as Ashes of the Singularity: Escalation, Assassin’s Creed Valhalla, Forza Horizon 4, World of Warcraft: Shadowlands, and others.

It’s Not A New Technology

Until now, the industry hasn’t heard of Smart Access Memory. It is something that was introduced in late 2020 by AMD.

Believe it or not, but this technology is not new. The original name of this feature is “Resizable BAR” and has been around for quite some time. Only now do we see the true potential of this feature after it has been properly optimized.

Once AMD introduced this idea, both Intel and NVIDIA have been working to bring it to every platform and GPU.

At the start of 2021, NVIDIA officially released Resizable BAR support for 3060 GPUs and laptops with RTX 3000 series graphics cards.

To use this feature, the NVIDIA GPU needs to be paired either with a Ryzen 5xxx, Ryzen 3xxx, Intel 10xxx, or Intel 11xxx.

Support may widen to older platforms over the next few years, but don’t get your hopes up.

Are Resizable BAR And SAM The Same Thing?

Resizable BAR

Is Smart Access Memory just a fancier term for Resizable BAR or are they the same thing?

Well, they are and they aren’t at the same thing. AMD’s SAM feature is originally based on Resizable BAR, but it’s been developed further to bring better performance improvement to the table.

Consider the fact that at the time of writing this article, enabling ReBAR on an RTX 3060 card won’t bring you any considerable performance uplift as reported by reviewers, and users.

Keep in mind things could change with additional BIOS and driver updates.

Future Of Resizable BAR

AMD has shown us only the surface of this new feature. In the future, we might see SAM or Resizable BAR bringing in even better performance boosts. Whether new variants of SAM or ReBAR will be backwards compatible, we don’t know.

Either way, the industry welcomes such new features and technology.

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Branko Gapo
Branko Gapo

Keeping up with the incredibly fast evolution of computer technology is impossible. That is why Branko will be using his knowledge on this matter to share news and information on all the latest essential technological innovations and advancements.