[TUF B850-PLUS WIFI] M.2_3 Slot Dead? SSD Not Detected even with Empty PCIe Slot

[NexusKr]

Hi everyone,

I’m encountering a frustrating issue with the M.2_3 slot on my TUF GAMING B850-PLUS WIFI. It seems completely dead, refusing to recognize a perfectly working SSD.

Current System Configuration:

CPU: AMD Ryzen 7 7800X3D (Using iGPU only, NO discrete GPU installed)

Motherboard: TUF GAMING B850-PLUS WIFI

BIOS: Factory Stock Version (Dated July 2025)

RAM: Crucial DDR5 5600MHz 64GB (Dual Channel, EXPO I enabled)

Storage Setup:

M.2_1: Samsung 990 Pro (OS Drive) -> Works Perfectly

M.2_2: Empty

M.2_3: WD Black 3D 1TB (Gen3 NVMe) -> NOT DETECTED in BIOS/Windows

Troubleshooting Steps Taken:

Lane Sharing Check: I am fully aware that M.2_3 shares bandwidth with the bottom PCIe x16 slot (4th physical slot). I currently have absolutely nothing installed in any PCIe slots. The bus should be free for the M.2 slot.

Cross-Testing: I moved the WD Black 1TB to the M.2_2 slot, and it is recognized instantly and works without issues. The SSD itself is healthy.

BIOS Settings: I've checked for any visible bifurcation or lane switch settings but haven't found a solution yet.

I noticed a thread from February 2025 describing the exact same scenario, but it ended without a solution: https://rog-forum.asus.com/t5/amd-800-series/tuf-gaming-b850-plus-wifi-m-2-3-slot/td-p/1076762

It's been almost a year since that post. Has anyone managed to solve this? Is this a known bug with the B850 chipset handling Gen3 drives in the chipset-linked slot, or is it a physical defect common to this board?

Any advice would be appreciated before I start the RMA process.

Thanks.

[p0k3m0n]

Disable in BIOS:

Platform Misc Configuration -> PCI Express Native Power Management (ASPM)

and everything that is connected to it, up to PCI Express Clock Gating.

I'm having a similar issue, but the drive works for a while, and then it simply disappears from the M.2_3 port. The drive is 100% functional.

Please give a feedback.

[NexusKr]

Exactly. I actually sent my motherboard in for testing, but they told me it was completely fine. When I tested it myself, the drive showed up at first, so I was relieved and thought I was good to go. But once I booted into Windows, it disappeared. I checked the BIOS again, and it wasn't being recognized there either.

[p0k3m0n]

Unfortunately, in my case, it turned out that the NVMe drive (Kioxia 1TB from BG6 series) had a faulty controller. Replacing the drive fixed all detection issues. It now works even with ASPM enabled.

[NexusKr]

That's good to hear! I just gave up on it and decided to use the M.2_2 slot instead. Since the RMA center said the board is completely fine, I'm guessing it'll work properly if I buy a new SSD later.