Just in case someone else have this problem, here is one possible problem and solution.

Your network card might be set to auto-negotiate speed settings, which doesnt always work as it should. For example, my realtek 8169 was set this way and it didnt allow changing of the settings (with ethtool or mii) either. Luckily, my motherboard have 2 network cards and the other one works with the forcedeph driver. This one also allows changes.

So setting the speed to 10 Mbit full duplex with no auto-negotiation gave me the normal full speed upload. The default of 100 Mbit full duplex (auto-negotiated) gave me uploads at about 20kb/sek instead of 1MB/sek...

Just posting this if someone have the same problem and is possibly finding their way here through google.