Downloading has TOO much priority, temporarly halts uploads

[Borisz]

I have noticed this since I was using cable (2007 october). When I download something at high speeds, 1-2 megabits, utorrent will almost immediatly quit all uploads - they will lose all their connections. At first I was thinking this happens because I don't have the bandwith to do simultaneous download/upload. But since, I've switched to an optical connection (30mbit up/20mbit down, simultaneously), and this problem persists.

So, a typical scenario is like this: I have 10-20 torrent seeded, they all go at various speeds (some hit 1mbyte, some only at 5k, etc). I seed as many torrents as possible to max out my upload - I have the resources the handle a high amount of connections. Then I add a torrent that has many seeds, mostly at seedboxes, so it can easily max out my line (2-3mbyte down). When I do this, the download will crawl to max speed as fast as it can, but at the same time, all my uploads will suddenly start dropping like flies. They drop in speeds, then become completely inactive (as in, transferring no bandwith at all). After a few minutes, the uploads will start transferring data again.

Once the uploads restart the transfers, I can keep both my upload and download maxed out. But it is extremely frustrating that my upload speed is temporarly nuked just because I add a new download.

What could be the cause of this? It happened both on my cable connection (10/1, later 20/3), and happens on my current optical line (30/20). I've always kept the latest version of utorrent, not sure at which version the problem first occured.

[Switeck]

This problem has been mentioned before by others.

It seems to occur even if the message "DISK OVERLOAD" never appears.