Here are a couple of scenarios where the current QM fails to take full advantage of available bandwidth:

1. Seeding. After a long time with no limit set for the number of active seeds, I set it to two, hoping that I could go ahead and seed a couple up to a decent ratio and then move on to seeding some others, eventually getting all seeds to a decent ratio. The problem is, the QM has at the top of the list two torrents that have far more seeds than peers, so there aren't any peers requesting chunks, so it's not seeding anything, period. I could manually move others to the top of the list, but I shouldn't have to do that.

KTorrent needs a smart auto-ranking system like Azureus that automatically reranks seeds based on seed/peer ratio and local share ratio. If Torrent A has a local share ratio of 0.25 and a seed/peer ratio of 4:1, but Torrent B has a local share ratio of 0.5 and a s/p ratio of 1:3, Torrent B should be moved to the top of the list and seeded instead of Torrent A, because Torrent B needs seeders more than Torrent A.

2. Downloading. Again, after a long time with no limit on the number of torrents, I set it to five for downloads, hoping that instead of downloading a tiny bit of many torrents at the same time, it would just download from five at a time, finish downloading them, and move on to download others. The problem arises when some torrents' download speeds drop very low. I have my download speed limit set to 20KB/sec at the moment, but it's only downloading 5KB/sec because the five active downloading torrents are just slow.

KTorrent needs a smart option like Azureus to increase the number of downloads, even past the limit, up until the download speed limit is reached, so that KTorrent makes best use of available bandwidth. Every 15-30-60 seconds or so, KTorrent should reevaluate the situation, and if KTorrent has exceeded the download number limit, it should stop some downloading torrents if it can reach the download speed limit with fewer torrents. In other words, KTorrent should download just enough torrents at the same time in order to max out the bandwidth setting, and if some higher-priority torrents speed back up again, it should pause the lower-priority torrents so they don't slow down the higher-priority ones.

Please consider adding these features to KTorrent. And please keep up the great work on the best BitTorrent app!

Azureus has pretty good queuing system, I agree. I was planning to redesign our queuing system too, but it would require some major changes so I left that to do when we port KT to KDE4.