Poor performance using Static IP

Good morning. I recently had my Business Class service upgraded to the highest speed tier available in our area (1.25 Gbps down / 35 Mbps up). As part of the "upgrade" my modem was replaced. Since the modem was replaced, my network's performance has significantly diminished. There appears to be an artificial rate limit imposed on the modem restricting speeds to a fraction of the theoretical maximum. I get about 95 mbps down and around 33 up. 

The current modem is a Technicolor CGA4332COM, hardware version 2.3. 

I've opened multiple tickets and a technician visited our site to troubleshoot the issue. He observed the poor performance over the static IP but attributed it to my local network. I explained that the only change to the network was the Comcast modem. He left and closed the trouble ticket. 

There is a similar post here: https://forums.businesshelp.comcast.com/conversations/domain-namesstatic-ip/slow-upload-on-static-ips/61b292e1e41a4a46af41a768 so I am not the only customer having these issues. 

If my ticket had been escalated instead of being closed, I feel that someone with the Network Operations team would have resolved it by now. Unfortunately, I'm stuck in a support loop so I am turning to the forums for help.