Do some test my ping testing to the various test my test servers and post back with those results.
I do not know how stable you can expect your results to be using Ethernet in your house at this high ISP plan speeds. If you’re not connected directly to the modem gateway then wiring length and quality may be coming into play. Outside your house, I don’t know how stable their system is either at those high speeds. My plan is a Charter (Time Warner) 200 Mbps plan and it varies about +/- 10 % typically Round 210 Mbps. That’s via wireless. The one computer I have that’s connected via Ethernet typically maxes out around 150 Mbps though. Not sure if that’s because my house cabling is CAT5E instead of CAT6.