Check Ethernet speed on a dual-band router

Your laptop is plugged into a dual-band router, but downloads still seem slow. A wired connection does not use the router’s 2.4 GHz or 5 GHz Wi-Fi bands, so changing bands will not fix a problem on the Ethernet cable.

First, measure the connection from your computer to the internet. Then check whether the result points to the router, cable, computer, or internet service. TooLab’s Speed Test measures download speed, upload speed, ping, and jitter in your browser.

Test your Ethernet connection

1. Connect your computer to a LAN port on the router with an Ethernet cable. If you use a USB adapter or dock, connect the cable through it as you normally do.
2. Turn off Wi-Fi on the computer temporarily, so it cannot use the wireless connection instead of Ethernet. On a laptop, keep it plugged into power if that changes its performance.
3. Open the Speed Test and run a test. Note the download speed, upload speed, ping, and jitter.
4. Run two more tests a minute apart. Close downloads, video streams, and other activity that could use the connection while testing.
5. For comparison, turn Wi-Fi back on and run the test again in the same room. Keep the computer, browser, and test server the same if possible.

The test sends data between your browser and a TooLab server to measure internet performance. It does not measure the maximum speed between two devices on your local network, and the server or internet route can limit the result.

What the result means

Ethernet is consistently faster than Wi-Fi

The wired connection is working, and Wi-Fi may be affected by distance, walls, interference, or the band your device uses. If wireless performance is the main concern, compare the 2.4 GHz and 5 GHz connections near the router and in the room where you need coverage.

Ethernet and Wi-Fi reach about the same speed

This may be the limit of your internet plan, the router’s internet connection, or the test route. It does not automatically mean the Ethernet cable is slow. Compare the result with the speed your provider advertises, keeping in mind that a plan’s stated rate is usually a maximum rather than a guaranteed result at every moment.

Ethernet stops near 90 to 95 Mbps

This often points to a connection negotiated at 100 Mbps rather than 1 Gbps. Ethernet uses some of the link capacity for network overhead, so a 100 Mbps link usually cannot deliver a full 100 Mbps in a speed test. A cable, router port, adapter, dock, or computer port may be limiting the link.

Results jump around or the connection drops

A single speed result can vary because other devices are using the network or because the internet route is busy. If repeated tests show large changes, disconnects, or much lower upload than expected, try another router port and cable before changing Wi-Fi settings.

How to improve the wired speed

1. Check that Wi-Fi is off during the wired test. Otherwise, the computer may still send traffic over Wi-Fi. Confirm the Ethernet connection is active before running the test.
2. Use a LAN port on the router. Plug the computer into one of the router’s LAN ports, not the port labeled WAN or Internet. Try another LAN port in case one is faulty or configured differently.
3. Check the reported link speed. In Windows 11, open Settings › Network & internet › Ethernet and look for Link speed (Receive/Transmit), if available. A value of 100 Mbps suggests the connection is not negotiating at gigabit speed. On macOS, check System Settings › Network › Ethernet to confirm the connection is active. macOS may not show the negotiated link rate there, so check the adapter or router diagnostics if you need that figure.
4. Try a different Ethernet cable. Make sure both ends click firmly into place. Test with another known-good cable, especially if the current one is kinked, pinched, or has a damaged connector.
5. Bypass the dock or adapter. If your computer has an Ethernet port, connect the cable directly. Otherwise, try another USB port or adapter. Check the adapter’s specifications: a 100 Mbps adapter cannot provide a gigabit link.
6. Check the router and computer ports. Some routers have a mix of 100 Mbps and gigabit Ethernet ports. Confirm the port and computer network adapter support the speed you expect. On Windows 11, check Settings › Network & internet › Ethernet for connection details. On a Mac, check System Settings › Network for Ethernet status.
7. Restart the router and computer. Restarting can clear a stuck connection or a temporary router problem. After they reconnect, run the test again with Wi-Fi disabled.
8. Contact your internet provider if the wired result remains low. If a direct Ethernet connection is far below your plan’s expected speed after checking the port, cable, and adapter, ask the provider to check the modem, service line, or account provisioning.

Why the Wi-Fi bands do not change Ethernet speed

A dual-band router broadcasts Wi-Fi on two radio bands, commonly 2.4 GHz and 5 GHz. Ethernet carries data through a cable, so neither band sets the speed of your wired connection. The bands matter when you compare Ethernet with Wi-Fi, because wireless devices can switch bands and each band behaves differently with distance and obstacles.

The router still matters: its LAN ports, processing capacity, and connection to the modem can limit both wired and wireless internet. If Ethernet reaches the expected speed but Wi-Fi does not, look at the wireless connection. If both are slow, check the router’s internet connection and your service plan before replacing the cable.

For the clearest comparison, use the same computer and test server, and keep other network activity to a minimum.