Gigabit

hi

just recently purchased my own modem which is a Arris T25 Gigabit Modem.i was able to successfully activate the modem using self activation for Internet and voice.noticed when i was using Internet i do not get the gigabit speed as advertised.i did a few different speed tests they all came back to 480-500 mbs.so i did some troubleshooting on my own disconnecting modem  resetting it also bypassing the router completely and still same results.i called Comcast went through all the troubleshooting steps at the end they said they need to send a tech out.i also reach out to arris the had me do some troubleshooting as well after looking at the results the tech said i am not getting a good signal coming from Comcast to the modem.just curious has anyone ran into this?my house was built in 2008 i do have a amplifier that was provided to me by Comcast.anyone help or advice would be appreciated.