The Speed.io speed test ☆☆☆☆☆
In general, the Speed.io speed test is not a recommended speed test. Speed.io has a misconfigured Speedtest Custom speed test, which doesn't work at all.
The screenshot say it all
The screenshot below makes it immediately clear why we did not test this Ookla clone in our standardized way. Even if the speed test worked, the results would be too predictable. That is, this Ookla clone is accurate, but slow and very inefficient in terms of data usage. In general, an Ookla clone is therefore not recommended.
Speed.io has a misconfigured Speedtest Custom speed test which results in a 404 error.