This guide helps find a limit between your device and router. A device's link speed is the rate of that local connection; it is not the measured speed of your internet service. Do not change router settings or force a network adapter to a particular speed or duplex mode.
1. Compare internet speed with Ethernet link speed
Compare the measured internet speed with the device's link speed. When connected by Ethernet, check the operating system's network details for the Ethernet link rate.
A low local link rate can limit a speed test, but a high link rate does not guarantee that the internet test will be equally fast.
2. Check your Wi-Fi link rate
Check Wi-Fi link details, if available. Windows may show a link rate in the connected Wi-Fi adapter status; macOS may show a Tx Rate in Wi-Fi details; some Android devices show link speed in the connected network details.
Menu names and availability vary by operating-system version and device maker, so use current manufacturer help if you cannot find it. The displayed rate is a connection estimate, not an internet speed result.
3. Compare another device
Compare another device using the same connection. If only one device has a lower link rate or speed, its network adapter, cable or capabilities may be the limiting factor.
If several devices show a similar result, continue with slow-speed troubleshooting or Wi-Fi versus wired speed.
4. Try another Ethernet cable and LAN socket
If using Ethernet, try a known-good cable and an accessible LAN socket. Change one item at a time and repeat the same test.
If the link rate or test changes, note which cable/socket was used. Do not move the cable connected to the NBN equipment or access router administration settings.
5. Record your device and test details
Record the device and adapter model, operating-system version, connection type, displayed link rate and repeated test results. Ask the device manufacturer about its adapter capabilities if needed.