Apple :: Poor Torrent Speeds With Transmission

Using Transmission to download a torrent, I've noticed that download speeds are consistently hovering around 15% of what my connection is capable of downloading -- which is to say, it's still a triple-digit kb/s, but quite a bit slower than it should be.

In Transmission, my port setting tells me that the chosen port is wide open, which leads me to think that neither Snow Leopard's firewall nor my Time Capsule / router is getting in the way, even without me checking specific settings. The download speed in Transmission is set to unlimited, and even if I set upload speed to 60% of what your usual residential cable internet line can handle, there doesn't seem to be an improvement.

The online Glasnost test tells me that there is no ISP throttling being done.

The torrents can have anywhere from seven seeds to dozens, to hundreds, and into the thousands, and can be left to run for minutes to a couple of hours. It doesn't matter. I've also seen torrents connected to north of 300 seeders without an improvement in speed.