So I've been having problems on and off with the Roku as far as dropping to 2 dots. Seems to drop for weeks, then I'll have weeks of 4 dots and so on and so forth.
Best results I've had is switching DNSs sometimes, unplugging the Roku & router, and then starting back up.
Was doing with OpenDNS and had two DNS servers working well then they went bunk.
Anyway, I read about a service called Namebench on Lifehacker which is just a small program and you install then it looks at your location and after a few minutes of testing spits out your optimal DNS servers based on speed.
I ran it, showed me that my OpenDNS servers were indeed not optimal and I switched to their recommended servers. Knock on wood I've been good for the last week.
If you're having streaming problems, I suggest you try the same. You can just google them and I'm sure it will come up.
Just thought I'd pass it along, as I know I've come to this forum in the past frustrated with streaming problems and hopefully this helps you out.