I've found this after upgrading fron 1.2 to SVN.

Upload speed reported by KTorrent on the status bar is much lower than the real upload speed.

For example, at this moment KTorrent reports 0-10kB/s, but the real speed is about 30-40 kilo...
I'm sure it's all made by KTorrent, becouse, when I close it, upload drops to 0 momentally.

The upload speed reported by KT is the upload speed of data.

We think most of the overhead is caused by incoming and outgoing connection attempts. We still have to deal with this problem.