Has everyone else found that Roku's built in speed test is worthless?
I am hardwired via a Gigabit Ethernet with fiber to home gigabit internet. When I run speed test I get 58Mbs onetime then 73Mbs the next it gives me a different answer almost every time.
Yes, I've never found any speed test on Roku to be accurate. Speedtest.net had a Roku channel for a while, and it was just as bad. The speed test built into the Netflix isn't any better. No idea why, but they've never been accurate.
Netflix tops out at 16 Mbps on 4K. Don't know precisely for Prime or Vudu, but likely about the same. However, when streaming my UND rips on my local network I can easily exceed 100 Mbps. All of my Roku devices buffer with them. For some reason my 5 GHz wireless isn't any better than just using the Ethernet. I have to use my Shield for my UHD rips, since it has a Gigabit jack.
Don't forget that speed is also determined by whatever wifi card is in the Roku, a quick search didn't yield any answers, but i doubt it's very speedy to a) keep price low and b) because it's just not needed to stream as has already been pointed out. For example, a $350 Acer desktop tower i looked at recently has an Intel wifi card that tops out at 450mbps, so imagine what's inside a $100 Roku or a $30 Express.