I built a new PC with a Gigabyte B850 Aorus Elite WiFi7 motherboard and installed the drivers. Using the same Ethernet cable that delivered gigabit speeds on my old computer, this new system only reaches around 10 Mbps. Windows confirms that the connection is Ethernet rather than Wi‑Fi, and the reported aggregated link speed is 2500/2500 Mbps. What could be causing the actual download speed to be so low?
4 Answers
Check that Windows is actually using the wired adapter. In Network and Internet settings, confirm Ethernet is connected and temporarily disable Wi‑Fi so there’s no possibility that traffic is going through the wireless connection.
As a troubleshooting step, open an administrator Command Prompt and run `netsh interface tcp show global`. If TCP receive auto-tuning is disabled, run `netsh int tcp set global autotuninglevel=normal`; if it is already normal, you can test `netsh int tcp set global autotuninglevel=disabled` and retest. This is not the most likely cause, but it has fixed unusually slow transfers in some Windows setups.
Make sure the motherboard’s Realtek LAN driver is installed correctly. It may be worth uninstalling the current driver and trying an earlier version from the motherboard manufacturer’s support page, since a bad or problematic driver can limit real-world throughput even when the link negotiates at 2.5 Gbps.
The Ethernet driver is installed, but I’ll try removing it and testing an earlier version.
Since the negotiated link speed is 2.5 Gbps, the cable and port have established a fast connection. That points more toward a driver, adapter setting, background traffic, or TCP configuration problem than a basic Ethernet link issue. Check for downloads, cloud sync, or other high-bandwidth activity while testing.
Windows shows the connection as Ethernet, and the negotiated link speed is 2500/2500 Mbps.