The USB Ethernet dongle, just how awful is it?
 

Noticed this on a friends setup, on a machine which actually had a perfectly good Ethernet adapter (Intel Pro/100 VE).

On 30Mb, I tested it & got 6.
So, tweaked up the Intel with the latest drivers, pulled the ProSet tuning a couple of clicks back toward computer performance, and swapped over.
BANG, straight up to 30 on the same test server, without even putting the RWIN tweaks in.

So, if you ARE using ye olde blue USB pod, because that's the way it was set up, do yourself a favour and use the system adapter if it has one, or go for a PCI card if it doesn't