Having Loading issues with latency on EA6350 with Xfinity using Arris

[crazyTIle]

After setting up Comcast / Xfinity to this.. everything worked fine. I notice after 2-3 weeks... the loading of pages dropped quite a bit. Did anyone had to tweak this router or is there other similar ones that can improve sluggishness of this router. There are like 6-7 devices connected but are not on all the time. Maybe only 1 PC connect by gigabit cat 5 directly. it is still a little slow to load pages. Should I mess with the MTU settings in Advance? Suggestions? It is not like totally slow.. but still when loading of pages it hiccups sometimes and Skype video Conferencing or Facetime suffers.. same as NetFlix