Yesterday we activated our new service with a new modem for 400mbs but am still getting the same speeds that I had before the upgrade. Have reset my modem and made sure all my equipment is up to date not sure what to do.
Visit https://mydeviceinfo.xfinity.com to determine your assigned speed tier. After you log into your account, your speed tier will be displayed on the left-hand side of your screen. Alternatively, you can view the speed tier to which you are subscribed here. Sign in and scroll down to the data usage graph area.
Are you testing your speeds directly connected to the modem via ethernet? What modem do you have? (Make/model)