The internet speed test measures the speed of your connection using a server that is closest to you geographically. This is a good way to know if you are actually the value on speed as promised by your internet service provider. But on the other hand, an internet speed test will not calculate the precise transfer speed of a file whether you are uploading or downloading something over the internet. There are lots of variables that may render the test unreliable as well as other things that are no longer under your ISPs control.
How It Works
The internet speed test works first by pinging the connection. This process sends HTTP requests to a particular server and then measures the period of time before it gets a response. After that, the download speed will be measured. Your PC will download small binary files from a web server to the client. The download speed will be measured to assess the connection speed.
For upload testing, a small volume of random data will be generated from the client and send it to a particular web server and then assess the connection speed. Depending on the speed test program, basic software often use between three and four HTTP threads in order to flood the connection.