AMD is investigating user complaints of USB devices briefly disconnecting on 500-Series motherboards when using a Ryzen 3000 or 5000 series CPU. It seems that the issue is exacerbated when using a PCI-E 4.0 GPU, so some users have rolled back to PCI-E 3.0 via a BIOS setting which has helped, but not eliminated, this issue. AMD is asking users impacted by this issue to gather information, such as steps to reproduce this issue, system logs, and relevant system info to help track this down.
The problem could be related to the amount of data flowing between components. Some workarounds proposed on Reddit try to reduce the volume of data flowing, by switching the system to PCIe 3.0, for example, or by disabling dispensable ports/devices. Another workaround, disabling global C-states (which is the CPU’s version of sleep), is an attempt to improve the system’s ability to handle the data.
One Redditor, fed up with an unusable system, asked AMD to refund their CPU. In their email declining the refund, AMD recommended updating the motherboard’s software, and if the issue persisted, to try disabling C-states and switching the system to PCIe 3.0.
AMD has since officialized the advice. In their words:
- Verify that your motherboard is updated to the latest BIOS version and configured using optimized/factory default settings. Check your motherboard manufacturer’s website for BIOS update and download instructions.
- Check if your Windows 10 is on the latest build and fully up to date. For information on updating Windows 10, please refer to Microsoft article: Update Windows 10
- Ensure that the Ryzen chipset driver from AMD is installed and up to date. Latest Ryzen chipset driver version is 2.13.27.501 and can be downloaded here.
And if that fails, then “consider using either of the following workaround:”
- Set PCIe mode from Gen4/Auto to Gen 3 in the BIOS
- Disable Global C-States in the BIOS
In their email, AMD reiterates that their “engineering team is actively investigating this issue with high priority.” While AMD’s deference to the community doesn’t say good things about their engineering team, at least they’re humble enough to recommend advice that works. Make sure to let AMD know on their Reddit post regarding this issue. Hopefully this is not a hardware level issue and will be fixed in later AGESA updates.
