Constantly Seeing 1/10 of Expected Speeds on XB7 Via Ethernet

Hello, apparently I have stumped the technicians at Xfinity.  I have the Xfinity XB7 Gateway with promising 1.2gbps speeds.  I CONSISTANTLY receive exactly 1/10 of this (about 90-100 mbps) every time I perform a speed test.  Before anyone asks, here are a few bullet points:

• I have witnessed 950gbps speeds before via my ethernet connection (which is what I would expect) so I know my hardware setup is capable. I replaced my current XB7, thinking it was the issue and immediately began receiving 900+ mbps speeds for a couple of hours. The next morning, I was back to 90-100mbps speeds.
• The computer I constantly test speeds with is a Windows 10 64 bit machine, connected straight to the orange port of the XB7 via a CAT5 ethernet cable – no switches! My NIC port is capable of Gigabit speeds.
• A Xfinity tech came out recently and replaced several Coax connections to reduce “noise”. This did not help.
• Another Xfinity tech tried to help me over the phone by changing setting on his end but was unsuccessful.
• On the Xfinity Home app, my XB7 Gate always sees more that 1gbps coming in so that is not a problem.
• I have fiber optic to my home and every room in the house has a dedicated ethernet run.
• My Wireless speeds are actually FASTER than my ethernet speeds. Getting about 300 mbps via Wifi when tested on my iPhone.
• Performed windows settings via the command prompt but nothing helped.

So, my questions are, why am I constantly seeing exactly 1/10 of what I should be?  How is it that I have witnessed 900+ mbps speeds before but now I don’t, without anything changing?  Any help and advice would be greatly appreciated.  Thanks!