Enabling And Testing AMD’s Smart Memory Feature

AMD UnBARred

At the moment only a very few people can take advantage of AMD’s new SAM feature, those that own an RDNA2 GPU and a Ryzen 5000 series processor running on a 5xx motherboard.  If that does describe your system, good on ya!  However you aren’t done yet as you need to take a quick trip to your motherboards manufacturer to double check you have the latest BIOS and install it if not.

From there, boot into your BIOS and look for CSM (Compatibility Support Module) and disable it as you are already using UEFI so why bother having it enabled?  Next you will want to look under your Advanced or Setup tab to find the IO settings as the next two features you need to enable should be hiding there.  First you want to enable Above 4G Decoding so you are not limited to a 4GB memory address space.  Right below it you should see Re-Size BAR Support (Base Address Register) which you also need to enable so that you can take advantage of the resizable register which has been a feature since PCIe 3.0, if not ever used for your GPU until now.

You might be wondering if this is worth it, certainly TechPowerUp did, which is why they tested out an RX 6800 with and without SAM enabled.  The results were quite obvious, albeit not always in a positive way as some games simply disliked this new feature.  Borderlands 3, Godfall and Assassin’s Creed Valhalla all saw performance improve by over 15%,  Cyberpunk, Metro Exodus and DOOM Eternal didn’t see any change while Apex Legends and Serious Sam 4 saw performance drop by almost 10%.

Take a look through the three dozen games they tested to see how you will benefit or suffer with SAM enabled.  Unfortunately, it is not as easy as Rage mode to switch on or off, you will need to reboot and disable the 4G and BAR features you enabled in order to turn it off.  Good thing many motherboards now let you save favourite settings in the BIOS, no?