Can I add a DST? Firmware updates?

[Kookyxogirl]

Hello, I purchased this cable modem to replace Comcast-Xfinity rental. I am happy that it will eventually pay for itself I am disappointed with the speed. I have a small home and was surprised that my wi-fi wasn't any faster after installation. I was wondering if I can add a DST? If so which one is compatible?
I have a DST 650 but that didn't work.
Also I was wondering if there are any firmware updates available for my new cable modem?
Thank you for your help in advance 😊

[DarrenM]

Hello Kookyxogirl

Have you ran speed tests on a PC connected to the modem? They could of messed up your internet speeds when you changed the modem on your comcast account.

DarrenM