Following are some steps you could take to troubleshoot the issue:

1. Test your internet connection speed at a few different sites. Compare the results to make sure your speed is the same on both devices.
2. Check to make sure your mobile device is connected to the same Wi-fi network as your computer.
3. Turn off any applications you have running on your mobile device that might be consuming bandwidth.
4. Check the settings on your mobile device to make sure the network connection is set to the highest speed available.
5. Ensure that the bandwidth of the mobile device is not being reduced by an antivirus or firewall.
6. Confirm that no users in your household are using the mobile device's bandwidth for downloading files or streaming content.