If you’re using Ryzen 4000G or Ryzen 5000G APUs, you may encounter a rare Windows boot issue, particularly with large 2x 32GB RAM configurations on A520 motherboards. These APUs, part of the Zen 2/Zen 3 lineup, offer integrated graphics, eliminating the need for a dedicated GPU.
However, the A520 chipset has a known compatibility issue when trying to install more than 64GB of RAM, especially with high-capacity 32GB DDR4 sticks in a 2x 32GB setup.
The problem arises from the system struggling to initialize the integrated GPU with over 64GB of memory, leading to Windows boot failure. This can occur even if the RAM is set to its base clock speeds and no adjustments are made in the BIOS. While some might find themselves stuck, there are two main fixes to resolve the issue:
Use a discrete graphics card: This solution is more expensive but guarantees compatibility.
Adjust BIOS settings: A more budget-friendly option, you can tweak the Advanced PCI Configuration and Advanced AMD CBS settings. To do this, disable the “Above 4G Decoding” option found in Advanced -> PCI Configuration, and set the “UMA Frame Buffer Size” to 4G and “UMA_SPECIFIED” under iGPU Configuration (located in AMD CBS -> NBIO Common Options -> GFX Configuration).
By following these steps, you should be able to avoid the boot issue and enjoy the full potential of your high-capacity memory on a Ryzen 4000G or 5000G APU.