User Manual
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PRIME X399-A BIOS Manual
Legacy USB Support
[Enabled] Your system supports the USB devices in legacy operating systems.
[Disabled] Your USB devices can be used for BIOS setup only and cannot be
recognized in the boot devices list.
[Auto] Your system automatically detects the presence of USB devices at startup.
If any USB devices are detected, the legacy USB support is enabled.
XHCI Hand-off
[Enabled] Enables the support for operating systems without an XHCI hand-off
feature.
[Disabled] Disables the XHCI Hand-off support.
USB Single Port Control
This item allows you to enable or disable the individual USB ports.
Refer to section 1.1.2 Motherboard layout in your user manual for the location of the USB
ports.
1.6.9 AMD PBS
The items in this menu display the CPU-related information that the BIOS automatically
detects.
This item appears only when you install an AMD Ryzen™ processor.
Enumerate all IOMMU in IVRS
[Enabled] Allows the IOMMU on the primary CPU die to map all device-visible virtual
addresses.
[Disabled] Enables the IOMMU on both CPU dies to map device-visible virtual
addresses.
NVMe RAID mode
This item allows you enable or disable the NVMe RAID mode. Conguration options:
[Disabled] [Enabled]