When I tried some bandwidth monitoring tools recently I noticed something strange: My upload speed is twice as high on the network than it actually is going into the Internet. And when I browse the web it normalizes, you can see that here: http://imgur.com/ASv9d.png
(80kb is the real capacity)
The setup is as follows: PC(Ethernet) --> Router/Modem --> Phone Line (DSL)
Nothing fancy there, nothing else connected.
The connection has about 80kb/s upload. But most of the time 160kb/s are going into my network - repeatable with µTorrent as well as uploads to RapidShare (edit: those 2 correctly report the real bandwidth). I see that the figure is correct looking at the properties window of the LAN connection, the counter always moves by 150.000+ bytes. When I throttle the bandwidth lower it scales accordingly to 200%.
This has to be the weirdest issue I've encountered yet. It's not impeding functionality but it does make me go WTF.