Windows users with Ryzen 4000G or 5000G APUs may encounter boot issues when using high-capacity RAM. If you’re experiencing Windows boot failures with 64 GB or more RAM on these processors, particularly on an AMD A520 motherboard, you’re not alone.
Despite the A520 chipset supporting large memory sizes, these processors, which are part of the Zen 2/Zen 3 lineup, may face compatibility issues. The integrated graphics unit on these APUs can become problematic with high-density RAM configurations, especially when using 32 GB DDR4 sticks in a 2x 32 GB setup.
The nature of this issue lies in the iGPU’s trouble initializing with over 64 GB of RAM, potentially causing Windows to fail to boot. This problem can persist even when the RAM runs at base clock speeds without any BIOS changes. Fortunately, there are two potential solutions:
1. **Install a Discrete Graphics Card:** This straightforward fix involves adding a separate GPU to handle graphics processing, bypassing the iGPU limitations.
2. **Adjust BIOS Settings:** For a cost-free alternative, navigate to the BIOS and adjust two specific settings. First, go to “Advanced PCI Configuration” and disable “Above 4G Decoding.” Next, under “AMD CBS” in the “NBIO Common Options,” set the “UMA Frame Buffer Size” to 4G and select “UMA_SPECIFIED” in the iGPU Configuration.
These tweaks can help you overcome the boot issues and take full advantage of your high-capacity RAM without the need for additional hardware.
