The TCP Chimmney Offload feature was introduced in Windows Server 2003 SP2.  It can offload certain functions from the OS to the network adapter card.  A lot of our newer HP Servers have a Broadcomm Ethernet chipset that supports this function.   It isn’t without its issues.  To determine if it is in use you can run the netstat –nt command like this:

C:\>netstat -nt

 Active Connections

   Proto  Local Address          Foreign Address        State           Offload State
  TCP    192.168.4.97:445        192.168.4.13:2167       ESTABLISHED     InHost
  TCP    192.168.4.97:1433       192.168.4.95:3560       ESTABLISHED     InHost
  TCP    192.168.4.97:1433       192.168.4.95:3617       ESTABLISHED     InHost

The last column shows the offload status.  In this example the offload state is shown as InHost for all connections, so TCP offload is not enabled.