New drivers add performance-enhancing memory access to older AMD GPUs | GeekComparison

Slides of the AMD Radeon RX 5700 series
enlarge The Radeon RX5700XT.

GPU driver releases are normally not very newsworthy; they usually fix bugs, improve performance in some games, and add support for new GPUs. But owners of AMD Radeon RX 5000 series graphics cards of the last generation 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 gaming performance in some games by up to 15 percent.

SAM support was previously limited to the Radeon RX 6800 series (and Nvidia’s GeForce RTX 3000 series, which supports a largely identical feature Nvidia calls Resizable BAR). In addition to the correct GPU and drivers, you must also be running a supported processor on a supported chipset: a 10th or 11th Gen 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. Typically, your computer’s processor can only directly access 256MB of your GPU’s video memory at a time, and the memory requires dividing larger assets into smaller chunks for transfer. Customizable BAR removes that limit and noticeably improves performance in some games. A TechSpot test of 36 games with an RX 6800 GPU and Ryzen 5950X processor observed an improvement of up to 20 percent, depending on the game and the settings. However, for most games, performance improved by a much smaller amount or not at all. A few games even showed performance drops with SAM enabled, but never enough to make games unplayable.

Even with the new drivers and supported hardware, users of existing PCs will have to jump through a few hoops to ensure they take 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 may be called “Resizable BAR” or “Smart Access Memory”. Or your motherboard manufacturer might call it something weird and GPU-independent, like ASRock’s “Clever Access Memory”. You may also need to enable a separate but related feature called ‘Above 4G Decoding’.

AMD says the release of the Adrenalin 21.9.1 driver is also the first to officially support Windows 11, adding support for automatic overclocking Ryzen 5000 series CPUs when 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 no matter which GPU you use.

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