x470 Taichi PCIe bifurcation problem

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   Sounds like BIOS bug.  You should contact AsRock tech support for that.
In the mean time, you can stay at 5.10 as NDRE28 suggested.

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eccential Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 10 Oct 2022 Location: Nevada Status: Online Points: 5735	Post Options Post Reply Quote eccential Report Post Thanks(0) Quote Reply Topic: x470 Taichi PCIe bifurcation problem Posted: 20 hours 36 minutes ago at 4:40am
	Sounds like BIOS bug. You should contact AsRock tech support for that. In the mean time, you can stay at 5.10 as NDRE28 suggested.

NDRE28 Members Profile Send Private Message Find Members Posts Add to Buddy List Senior Member Joined: 08 Sep 2024 Location: Romania Status: Offline Points: 1425	Post Options Post Reply Quote NDRE28 Report Post Thanks(0) Quote Reply Posted: 22 hours 57 minutes ago at 2:19am
	Hi! I'd downgrade the BIOS version to the one that worked well (v5.10). Sometimes, new BIOS versions are worst, in some areas, than the old ones.

aswin Members Profile Send Private Message Find Members Posts Add to Buddy List Newbie Joined: 17 Mar 2025 Status: Offline Points: 20	Post Options Post Reply Quote aswin Report Post Thanks(0) Quote Reply Posted: 17 Mar 2025 at 10:11pm
	Hello, I am experiencing an issue with the PCIe bifurcation (PCIe x16 switch) feature after updating the BIOS beyond version 5.10. My current configuration is as follows: PCIe Slot 1: GPU installed. PCIe Slot 3: Uses a PCIe-to-U.2 converter to support two NVMe U.2 SSDs. PCIe Slots 2, 4, and 5: Each occupied by an SSD. M.2_M1 Port: NVMe SSD installed. With BIOS version 5.10 and earlier (including 4.xx), all SSDs are recognized correctly using PCIe bifurcation in an x8/x4/x4 configuration. However, in BIOS versions 8.xx and 10.xx: When PCIe bifurcation (PCIe x16 switch) is enabled, the NVMe SSD in PCIe Slot 4 is not recognized. When I disable PCIe bifurcation (by setting it to x16 mode), the NVMe SSD in PCIe Slot 4 is recognized, but the two U.2 SSDs in PCIe Slot 3 (via the PCIe-to-U.2 converter) are not recognized. This issue does not occur in BIOS 5.10 and earlier.Any idea?