Whenever I start a PC game, my wired internet connection completely stops working for around eight minutes or more. This happens across multiple games, including Marvel Rivals, but browsing and other normal internet use remain stable for hours. My phone stays connected over Wi-Fi during the outage, so the router and internet service seem fine. Closing the game eventually restores the connection automatically.
The PC uses a Realtek Gaming 2.5GbE Family Controller over Ethernet. Windows Event Viewer does not show any obvious network-driver crash or critical error when the disconnect occurs. I have already disabled the adapter's power-saving option, Energy Efficient Ethernet, and Green Ethernet; reset the Windows network stack; clean-installed the Realtek driver; and tested another Ethernet cable and different router ports. What else could cause the connection to fail only while gaming?
3 Answers
Open the Ethernet adapter's advanced properties and check Speed & Duplex. Instead of leaving it on Auto Negotiation, try setting it manually to the speed your router or switch supports, such as 1.0 Gbps Full Duplex. A negotiation problem can show up under heavier network activity.
While the game is running and the connection appears dead, check whether a browser can still load websites. If browsing works but the game cannot connect, a firewall or network policy may be blocking the game specifically. It would also be useful to test the same game over Wi-Fi; that can help separate a PC-wide issue from a wired-adapter problem.
It may be worth checking whether the Ethernet controller is getting unusually hot once the system is under gaming load. Try temporarily removing the side panel or directing a fan toward the motherboard area and see whether the disconnect still happens. If extra airflow changes the behavior, investigate case airflow and adapter temperatures.
That seems unlikely without a blue screen or an Event Viewer entry, although a temporary adapter failure could still happen without producing a clear crash report.
If the network chip were overheating badly enough to cause this, I would expect other components or the whole system to show symptoms too, rather than only losing the connection.