XB8, WiFi Upload Speeds are good but Lan/Direct ethernet upload speeds are terrible

@danpojo Thank you so much for your post for help with using your ethernet ports on your new Xb8. Not all the ports are set up for internet connections. Some ports are designated to be used for phone services. Also, from my experience 3 out of the 4 remaining ports are capable of providing Gigabit extra speeds but the 4th is capable of supporting even more. This would go the same for upload speeds as well. If you have confirmed you are not using the voice ports I would try with a basic reset of your device after confirming if the correct modem is showing active in your Xfinity app. You can check out how to look that up here:https://www.xfinity.com/support/articles/my-account-view-equipment-information If your modem is showing correctly then I would unplug all the directly connected devices then unplug your modem from the power for at least 30 seconds. Once you have it plugged back in wait till your connection is fully restored before plugging the devices back into the ports. If you are still encountering issues, the troubleshooting option in the Xfinity app will help check your connections for specific devices to better help. 

@danpojo 

FWIW. You wouldn't be able to get any internet service at all out of the phone ports. And the phone ports and ethernet ports are distinctly different sizes.

Ethernet cables come with RJ45 connectors on both ends. Because of this, an Ethernet cable is sometimes designated as an RJ45 cable. These cables are often used to connect computers to Ethernet networks. The RJ45 connector resembles a six-pin RJ11 connector, though the 45 is slightly wider.