I highly recommend, if you are running Windows Server 2008 or Windows Vista, to disable the network scalability features. If you don't, you run the chance of one day running into "slow" performance of an application between one client or server and another. You will spend countless hours trying to debug why the network communication is so slow to that feature from that one client when it works fine for you and serveral others in the same area and with the same configuration. As far as I am concerned, TCP offloading has been a failure since the beginning, and I am not sure who is to blame, Microsoft or the hardware vendors. Oddly enough, I even saw the "symptoms" on a virtual server.
From an Administrator command prompt:
netsh int tcp set global rss=disabled chimney=disabled autotuninglevel=disabled