20 Mbps after upgrading to DOCSIS 3.0 modem

Um, probably.  There's a thread a few days old (Upgraded NEW MODEM DOCSIS 3.0 but speed still caps at 32 mbps!!) which had 279 replies last time I checked, that may be relevant.  Apparently, even though you registered the new modem with Cox, they may not have set the bit that says you are now at DOCSIS 3, so you are effectively capped.  Funny, though, most folks with this problem have been seeing 32 Mbps. 

I

Got the bit turned on by the technicians and I have 60 mbps now. Thanks