But the speedtest is not using the same path as you did when you noticed it running slowly. So results will vary. To understand this you have to understand the Internet which is on web articles or taught in classes.

On top of that many speedtests will select a server near you to give you the best results which will confuse folk that don't know how the Internet is built and works.

The short answer is speedtest results are your best speeds, not what you will get from everywhere.