Archie has a Wi-Fi router and has connected his Roku, but he's not getting good enough reception and it buffers a lot. Leo says the farther the router is from the Roku, the less connection can be made. But Leo also suspects that the router isn't giving Archie as much bandwidth as he needs. It could be due to congestion.
If his router supports the 5 GHz band, it's a much better choice for streaming. He can also take the old router and put it in bridge mode and use it as a repeater to pass along the signal.