While using BitTorrent for file transfers, I notice that my average transfer rate was really slow compared to my internet connection. It turns out that you must manually adjust various BitTorrent parameters in order to achieve a better than average transfer rate.

The following settings must be manually adjusted to your particular internet connection:

kB/s global max. upload speed

kB/s global max. download speed

Default max. upload slots per torrent

Maximum number of connections per torrent

Maximum number of connections globally

Max. simultaneous downloads

Max. active torrents

By manually adjusting these setting, I was able to achieve an average download rate that was typically 2x to 10x greater than the average Swarm speed — apparently most bittorrent clients out there are miss-configured, so beating the average swarm speed is easily achievable.

One other item that I still want to understand is why my download to upload ratio is so close. On average, for a 4GB file transfer I am ending up with a ratio of 0.7. I had expected a much bigger download ratio as a result of much faster download pipe.

Apparently, Clients will prefer to send data to peers that send data back to them, which encourages fair sharing. As a result, I am not able to download much faster than I am uploading — if I don’t send them data back, they won’t send me a new data chunk. The best I have been able to achieve is a 2-1 ratio. It is, in the end, a data sharing network, and you must be willing to share in order to play.

Cristiano Pierry

Optimizing BitTorrent transfer rate

Originally from Applepie by Cris

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