Super User is a question and answer site for computer enthusiasts and power users. It's 100% free, no registration required.

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

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.

share|improve this question
After watching the video, I suspect it is some kind of bogus info from the program. I would go to and do a real speed test, and compare it to what you ISP is supposedly giving you for speed. That is probably the real number. – KCotreau Jul 30 '11 at 1:56
@KCotreau, No Sir, it is not bogus, we do get that abnormally high speed, what video is not showing is that it lasts only for few minutes – USBGuy Jul 30 '11 at 2:09

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.

share|improve this answer

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.