what kind of network card are you using?
I noticed that some network card is slower than other network card.
also depend on what network template I use.
I also have a machine which shares the IRQ with soundcard.
when I disabled the soundcard from a bios, I got a lot faster speed.
even though you are in the same subnet, you might going through many different switches/routers.
if you can use a single hub with just console and client connected,
you can verify that it is due to your network environment or your network card.