torrent speed suddenly increased to 1mbps...?

[Arnav]

I was downloading a movie using bit torrent client....and suddenly my download speed increased from an average rate of 50kbps to 1.6 mbps....! It happens every now and then....but only for some torrents...
As soon as my movie was downloaded....i resumed my another torrent nd it gave me back my usual speed of 40-50 kbps....
Can any1 gimme a technical reason for this..as to why this happens....
Btw I have a cable connection for the internet which is 512 kbps(as they say,though the dwnld rate is in mid 40's)

[Mind Reader]

It happens with me too, I have observed that it happens when the port 53 is open... for me, the speed stayed as long as an active download was on progress or until the download session was active. I have noticed that when the download ends or if I logout and login from my internet account, the speed goes back to default. The best thing to do in such time is to start simultaneous downloads, i mean start downloading 3 or more torrents and utilize that session... and trust me, when port 53 is open, you might get about 10 MBPS speed... you could have downloaded 3 or more torrents on the same speed.... I don't know the reason for this abnormal speed increase, but when ever the speed increases abnormally, I have noticed that port 53 would be open... maybe a tech guy can give you more accurate answer....

NOTE: Downloading movies via torrent are not legal on most of the countries.