To troubleshoot your internet speed and see why it is different on different devices, try these steps:

1. Check your Wi-Fi connection. Make sure that the connections are stable, secure, and using the correct network name and password.
2. Check if your router is configured properly. Verify that you have the appropriate range of frequencies for your devices and that the router is using the right channel.
3. Check the settings on your devices. Make sure that your devices are set to the maximum speed supported by your router.
4. Check the settings on your devices. Make sure that your devices are set to the maximum speed supported by your router.
5. Check for software updates. Make sure that all your devices have the latest versions of firmware and software.
6. Test your Internet speed. Try using different online speed tests and see how your results compare with the advertised speeds of your Internet service provider.
7. Contact your Internet service provider. If none of the above steps has resolved your issue, contact your Internet provider for help.