I run on 70 Mbs internet down a phoneline. The company that did supply me with a 250 Mbs then couldnt keep a flat response graph at those speeds due to bad lines turned out to be a lot worse than the service I use now.
I flew MSFS 2000 on a 56k modem, so I am thinking the max bandwidth for this will be around the 5 - 10 Mbs as its never gone out of that range with live data and sattelite settings on.
Do an MTU check on what you have now, Im saving a fortune