@Heidi_Alp - thank you, QOS was the problem. Another user guided me to finding the QOS setting, somewhat hidden in the Homeshield section. I The problem was the QOS download speed was set at 600mbps,...

@Heidi_Alp Hi - Thanks for the suggestion. My understanding is that QOS is a premium feature inside a Homeshield subscription, which I don't have. So I would think my QOS settings are at default....

I have Comcast Gigabit service, and reliably get ~950mbps down / 40 mbps up when I connect a PC directly to the modem using an ethernet cable. When I connect the same PC using the same ethernet cable...