Upgraded modem, connection intermittent

Last week I upgraded to the Docsis 3.0 modem.  Since then my connection is nearly unusable during the day and somewhat usable after 9pm.  I'm on a wired connection, so I tend to think there is work being done on the network at the Cox end locally.  Any info would help greatly.

Start	Cox Net	Download Speed	Upload Speed	Latency	Your IP Address	Cox Market
Fri Sep 12 12:52 PM	Yes	0 Mbps	2 Mbps	38 millisec	68.2.123.134	Phoenix