I use the same settings that I had from when I was living overseas using a 1Mb DSL connection in a third world country.
What used to happen then was Torrents would eat 98% of the speed, and then everything would SLOW, not stop. So then I used to limit my torrent client to 50% of the 1Mb Connection.
I am using the same Linksys WRT54G I have always had, I now have an 8Mb connection, so that should not be a problem downloading one torrent from 54 peers.
I have also noticed this happens more towards the end of the month.It is approaching the end of the Sept. I can bet in 9 days at the start of Oct. the speed will be perfect, till about the third week in Oct. when it will start to slow again.
This never happened till about February 08, and I have been here just a year.