I have had the same trouble. I can still stream but not without lagging issues. I found an Ethernet to USB adapter and connected the TV directly to the router and now it flies. And I have noticed improved WI-fi connections with my other devices now that the Roku isn't hogging it all. My Roku is Model 40S325 and the adapter I used is here https://www.amazon.com/dp/B00MYT481C/
