I'm troubleshooting a very strange Ethernet problem on a PC with a Gigabyte B650 Gaming X AX V2 motherboard, revision 1.2. The onboard Realtek LAN port stopped working, so I installed a TP-Link PCIe Ethernet adapter that also uses a Realtek chipset. Both adapters are detected and show link/activity lights, but neither provides a usable network connection.
I have reinstalled Windows, updated the BIOS, installed the latest network drivers, removed and reinstalled both adapters, reset Windows networking, and tried commands such as netsh, ipconfig, and Winsock reset. I also checked that the onboard LAN controller is enabled in the BIOS and performed a full power discharge of the PC.
The problem occurs in both Windows and Linux, so it does not appear to be operating-system-specific. The Ethernet cable, router, and switch have been ruled out: the same cable and network work normally through a USB-C Ethernet adapter on this PC. The onboard LAN and the separate PCIe Realtek adapter are the only ones that fail.
Could this indicate a motherboard, PCIe, BIOS, chipset, or other hardware-level issue? What should I check next?
2 Answers
A Winsock reset is worth trying for a Windows-only problem, but it cannot explain the same failure in Linux. Since both Realtek adapters fail across operating systems while USB Ethernet works, the issue is more likely related to the motherboard, PCIe behavior, firmware, or a shared hardware dependency than to Windows networking settings.
As a basic hardware check, power-cycle both ends of the wired connection in sequence: shut down the PC and network equipment, disconnect their power briefly, then power the router or switch back on before starting the PC. This lets both sides renegotiate the link cleanly. However, since you’ve already tried a different router and the USB Ethernet adapter works with the same cable, this probably isn’t the main cause here.
I already tried that, including testing with another router, but neither of the Realtek-based adapters would connect.
That was one of the first things I tried, and it made no difference. The Linux results make a Windows networking issue seem unlikely.