What is happening to my Internet connection?

Question

I want to understand this strange thing happening with my Internet connection. I log into my ISP using their Web Interface to connect to the Internet. Now, after connecting to the Internet, I start downloading a file from a direct link (torrents, file hosting sites won't do) using Internet Download Manager. While the download is in progress I log out from my ISP.

This is when the magic happens, the speed at first decreases for a few second, but then it increases abnormally up to 2000%-3000% for a few minutes, and then it reduces and the connection drops.

I want to know what is happening and how can I sustain this abnormal high speed?

In case you want to see it in action, here is a video someone made, which shows exactly what I am talking about.

Answer 1

I did not have a clear view of what was going on at first.

I believe that what is happening is that you are downloading, and since you are using a download manager, it is buffering the data, and keeping a constant amount when you are connected, since your Internet connection is relatively constant. The data being written here is Internet to disk (buffer).

Once you close your Internet connection, the data and buffering stops, and it writes all the data that is left back to disk at a much higher rate since it is then disk (buffer) to disk (to file).

You can see a similar phenomenon if you watch your DVD software (if it has a visual buffering indicator) write a disk, and right at the end, as there is nothing left to buffer, is clears out very quickly.