Speedtest.net is a horrible way to test your internet speeds. The isps intentionally prioritize traffic to them because it makes them look good, and speedtest doesn't offer any actual services that could create legitimate traffic. At the very least use fast.com, which is run by Netflix and will show you what kind of performance you'll get to a real site. Ideally you'd test against multiple sources though, especially now that Netflix has started giving ransom money to some of the larger residential isps.
fast.com is a great way to evaluate your QoS to the Netflix CDN but in my experience it isn't a good way to test your general Internet-wide throughput. speedtest.net (with a sensibly chosen server -- not the default which will tend to be your ISPs) is better. Better still test to a server you control yourself.
Once again... speedtest.net is white listed by every ISP out there to give maximum speeds and bypass any throttling they have in place and typically gets placed in a prioritized queue. It's just slightly better than useless and will tell you nothing about your actual speeds during network congestion..
