New drivers add performance-boosting memory-access feature to older AMD GPUs

GPU driver releases normally aren’t very newsworthy; they usually fix bugs, boost performance in some games, and add support for new GPUs. But owners of last-generation AMD Radeon RX 5000-series graphics cards should take note of today’s Adrenalin 21.9.1 release. This update adds support for AMD’s “Smart Access Memory” (SAM) feature for older GPUs. AMD says the feature can improve game performance by up to 15 percent in some games.

SAM support was previously restricted to the Radeon RX 6800 series (and Nvidia’s GeForce RTX 3000 series, which support a mostly identical feature that Nvidia calls Resizable BAR). In addition to the right GPU and the right drivers, you’ll also need to be running a supported processor on a supported chipset: either a 10th- or 11th-generation Intel Core CPU in a 400- or 500-series motherboard or a Ryzen 3000 or 5000-series CPU in a 400- or 500-series motherboard.

Whether you’re talking about SAM or Resizable BAR, the different names all refer to the same PCI Express functionality. Normally, your computer’s processor can only directly access 256MB of your GPU’s video memory at a time, and the memory requires larger assets to be broken up into smaller chunks for transfer. Resizable BAR removes that limit and noticeably improves performance in some games. A TechSpot test of 36 games using an RX 6800 GPU and Ryzen 5950X processor observed an improvement of up to 20 percent depending on the game and the settings. For most games, though, performance improved by a much smaller amount or didn’t improve at all. A few games even showed performance decreases with SAM enabled, though never by enough to make any games unplayable.

Even with the new drivers and supported hardware, users of existing PCs will need to jump through a few hoops to ensure they’re taking advantage of Smart Access Memory. Start by installing your motherboard’s latest BIOS update (motherboard makers started adding support for Resizable BAR and SAM in late 2020 and early 2021). Then enter your BIOS settings and enable the feature; depending on your motherboard, it might be called “Resizable BAR” or “Smart Access Memory.” Or your motherboard manufacturer might call it something weird and GPU-agnostic like ASRock’s “Clever Access Memory.” You may also need to enable a separate but related feature called “Above 4G Decoding.”

AMD says that the Adrenalin 21.9.1 driver release is also its first to officially support Windows 11 and that it adds support for auto-overclocking Ryzen 5000-series CPUs when they’re paired with an RX 6000-series GPU. Overclocking Ryzen processors within Windows normally requires the separate “Ryzen Master” utility, which supports a wider range of processors and doesn’t care what GPU you’re using.