Xfinity Gigabit Modem vs my new Motorola MB8600 Docsis 3.1 - Slower Speeds with my Modem

I just connected my new Motorola MB8600 and it is slower than my Xfinity gigabit router. I am paying for 600 and was getting 500 to 700, depending on traffic,etc.

With the MB8600, I am getting in the 170 range. Is there anything I can check with settings to tweak things? Anything obvious to check? Does it take time to work it's way up to the faster speeds?