[Thulani]

I think you describe a normal thing if you're one of those people who download a torrent immediately after it has been uploaded on the tracker. Not many people have great upload speed so it's a normal thing that at a certain moment the download speed to go down.

Grab a torrent with 20-30 seeders and see if is happening the same phenomenon with your download speed. Also, the last version of utorrent is favoring connections with users using the same software. So if you use other torrent client expect to see slower speeds.