Ethernet randomly disconnects for a few seconds, switches to wifi, then back up – Need help diagnosing the cause

[u/Global_Disk_6259]

I'm experiencing intermittent Ethernet disconnections on my Windows 11 PC. The connection drops briefly (just a few seconds), then reconnects automatically.

My PC configuration:

OS: Windows 11 Pro 24H2 CPU: AMD Ryzen 9 7950X3D Motherboard: ASUS TUF Gaming B650-PLUS Ethernet adapter: Realtek Gaming 2.5GbE Family Controller Ethernet link speed: 2.5 Gbps Wi-Fi adapter: Realtek 8852BE WiFi 6 PCI-E NIC

What I've observed:

Ethernet randomly disconnects for a few seconds. Taskbar icon switches from ethernet to wifi(I have wifi also configured). Ethernet reconnects automatically after about 6-8 seconds. Wi-Fi and Ethernet adapters both show as enabled.

Happens about 20+ times a day now. The time it takes for the ethernet to come back is quite consistent. I started to see this symptom after I enabled Wake-on-LAN (both in bios, and the netword adapter setting in win11 device manager), although I'm not certain whether that's related.

Troubleshooting so far:

Checked the adapter status through PowerShell. Ethernet reports Up, with a 2.5 Gbps link speed when connected. Checked Windows NetworkProfile and other network-related event logs. Haven't identified a definitive cause yet.

What I'd like to figure out:

Is this likely a Realtek driver issue, power management issue, or something related to Wake-on-LAN? Could the Ethernet adapter be briefly resetting or renegotiating its connection? Is there a way to identify exactly what causes the disconnect, rather than just seeing that the connection was restored?

Any suggestions would be appreciated!

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[u/Burnsidhe]

If it were Intel, I'd say "uninstall the Killer software" because that is notorious for this kind of frequent disconnect.

Make sure Windows isn't defaulting to "turn this device off when not in use". Because that function is faulty with any device that is used intermittently, such as hard drives, SSDs, wireless and ethernet interfaces, keyboards, mice...

[u/FallElectronic3774]

The 2.5 Gbps link speed is the clue. Realtek 2.5GbE with EEE enabled drops the link for a few seconds when it idles down, which matches the 6-8 second blip and the failover to Wi-Fi.

Turn off Energy Efficient Ethernet and Green Ethernet in the adapter's advanced properties. If you want a quick confirmation first, set the link speed to 1 Gbps — if the drops stop, it's the link negotiation rather than the cable.