Interesting. Even over multiple tests, I get almost exactly 1/3rd the download b...

drewg123 · on May 18, 2016

This tool exists exactly to highlight cases like yours.

Sounds like your ISP has over-subscribed its connection to whatever IX is serving this to you, and that they're hosting speedtest locally in their network.

tracker1 · on May 18, 2016

More likely the speedtest sites have a much higher QOS definition, and are unthrottled, while netflix is explicitly throttled.

drewg123 · on May 18, 2016

It is probably both.

I'm a Comcast customer. When I run speedtest & tcpdump the traffic, i'm nearly always talking to something .comcast.net, and it is just a few hops away via traceroute.

When I use fast.com, I'm talking to various ix.nflxvideo.net hosts, all at least 4 to 6 hops farther away.

The amusing thing is that I get better speed with the fast,com (140Mb/s) than with speedtest (133Mb/s).