Torrent speed slows down after nearing completion

[Watabou]

Hi,
I think I'm the only one with this issue. I've noticed this on the last version of transmission and the current version. It happens to every single file that I add and is extremely frustrating.

When I add a torrent file, I get good speeds around 500kb/s but when the file is close to 90% done, it slows to ~5kb/s. If I add another torrent file, that added file will download at 500kb/s but then slows when it reaches ~90%. Can anyone tell me why this happens?

[redswill]

I'm not sure if this happens because of this, but here's my opinion:

The way torrents work is that they download the file in small packets. When you start the download, Transmission has a lot of packets to choose from and it can open up a lot of connections and reach maximum downloading speed. However, when the torrent reaches completion, Transmission has to download the last remaining packets. Due to fewer packets to choose from and probably low availability and few seeders, Transmission might have a hard time downloading at full speed. The last few packets that arrive just before completion are the worse, especially the last one.

In short, when you start a torrent, Transmission can download 100 packets from 100 different people, all at the same time.
However, for the last packet before completion, Transmission has to download that 1 packet from that 1 seeder, it can't open multiple connections.

I repeat, I have no idea if this is the way it works and I can't be bothered to research into it, I just thought I'd give my opinion until you get a proper answer.

[nash8114]

See previous post on this subject:
viewtopic.php?f=4&t=9781

Also, what version of Transmission and what OS X version are you running?

[Watabou]

@redswill: That makes sense but if I use Vuze(yuck), this doesn't happen.

@nash: Running 10.6.4 and transmission 2.01