Slow Internet Speed after upgrading from XB7 to XB8

The subject line says everything - should be getting close to 1.5GB/sec and am currently getting sub-Gig speeds.  My gaming pc (Intel I9-9900KS, ASUS XG-C100C 10G PCI-E Network Adapter) is directly wired to the XB8 using Cat7 cable.  I have rebooted the XB8 multiple times and no difference,  The Xfinity Chatbot suuuuuuucks, so I am ready to cancel all Xfinity services and go a different route.  Would be nice to be able to speak to a Level 2/3 tech support agent....