Upgraded my internet connection from 100mbps to 300 mbps but don't see much change. Another screw job from Comcast?
They may have upgraded you, but it's doubtful you would notice a difference as most people (except gamers) don't really push their bandwidth much.
I gave my old Roku to a friend with satellite internet (slow as can be) and it even worked fine with that. It just had to buffer the movies for a few seconds before they would start playing.
By the way, you can test your connection at the internet speed test site, if you want:
https://www.speedtest.net