Slow ethernet and WiFi with Xb7

I recently switch to the Xb7 and 1GB service and am thoroughly frustrated with the Ethernet and WiFi consistency speed. Cannot quanity how many calls and how much time I have spent with Comcast to no avail and no offer to send a tech. I have conducted countless speedtests at the router and have never gone over 600mbps. (First world problems I know. but it would nice to get what I pay for.)

Today I was checking speed via LAN and never got above 100mbps!! No one at customer support can help with this at all?! In the meantime, I notice this in the Gateway...When I go to Hardware and the LAN, eac of the four connections "Connection Speed:100 Mbps".

Can this have anything to do with the LAN speed? If so, how do I resolve it? Thanks.