Modem upgrade ?

I am running a old Motorola that is 4yrs+ old. I understand to take advantage of the faster speeds you would need a DOCSIS 3.0 modem. I was thinking about getting a Netgear CG3000D and was wondering if this is compatible with Cox so that I can get the speeds I been missing (smh lol) Also this particular model I can't tell if it is just for the modem or it is a combo modem/router. Thanks