I've resolved it—I'm still having trouble getting Windows to detect my Intel X550-AT2 card.
I've resolved it—I'm still having trouble getting Windows to detect my Intel X550-AT2 card.
Have you explored the option to install the driver from Intel?
The seller needs to be truthful, don't you think? If another device fits the same PCIe slot and you insert this card without triggering any unknown entries in Device Manager, it could mean you've purchased someone else's e-waste. I checked quickly online—there are definitely fake Intel X550 cards available.
The second PCIe X16 slot becomes inactive when a NVMe SSD is connected via the second M.2 port, since both devices utilize the same PCIe lanes from the motherboard. Refer to the manual, page 16 (29 of 357): https://download.msi.com/archive/mnu_exe...MAHAWK.pdf. If you have a M.2 device in the second slot, try connecting the Ethernet card to the bottom PCIe X1 port—yes, it’s perfectly acceptable for the edge connector to sit freely, as PCIe was built to allow modular lane configurations. The physical pins don’t need to be rigid at the end because of this design. Typically, you’d reach a theoretical max of 985 MB/s per lane, but in reality, the combined speed might drop to around 900 MB/s across both ports if it functions. EDIT: even without any M.2 device, some BIOS settings may switch to "Force M.2" instead of automatic or PCIe3 slot selection. Check the BIOS for this option. The Ethernet card uses PCIe X4 and should operate in slots with just one or two lanes, which is standard. However, certain manufacturers might disable lane operation on a single lane via firmware. If that’s the case, consider using a multimeter: set it to DC voltage, attach the black probe to a ground point (like the bracket), and the red probe to various locations to check voltages. The lack of detection usually means the BIOS is routing lanes to the M.2 connector. Another possibility is insufficient power reaching the card—verify with fuses near the edge connector and inspect inductors, components labeled with numbers like L<number>, or parts marked R56 and 2R2, especially in the top-right corner. On one side you should see 12V or 3.3V, while the other side shows lower voltages (3.3V, 2.5V, 1.8V), which are typical for chips, RAM, etc.
I was using drivers from Intel’s website (Intel Ethernet Adapter Drivers). I experimented with various versions and the "Intel Driver & Support Assistant." Eventually it worked—I removed my SSD from the second M.2 drive and Windows finally recognized the NIC. Reading the manual on the motherboard gave me a wrong idea about compatibility, but proper installation order resolved the issue. I attached my BIOS settings. I tried adjusting the chipset switch and "Auto" settings, but the NIC still wouldn’t appear. Once I swapped out the SSD, Windows detected it correctly, and everything functioned properly. Now I’m stuck because my second M.2 slot isn’t working. This motherboard has been a real challenge.
EDIT: Found more details on the MSI forum for B550 Tomahawk – M2_2 and PCIE_3. It seems replacing the NVMe SSD in the M.2 slot with a SATA SSD or upgrading to a larger drive in the first slot might be necessary. This setup is definitely tough. Updated April 7, 2024 by odlaw.**