On Windows 2003 Enterprise Edition Service Pack 2 TCP Chimney was enabled by default. It took me a while to discover this feature. But once I did find it , I turned it off.
It was causing numerous problems on many applications , particularly modelling based , long running SQL Server transactions. I also experienced problems with Microsoft Exchange.
Windows 2008 still has the TCP chimney offload functionality but the command syntax has changed. On the article there is a command that shows the status & it seems that the chimney is disabled by default anyway.
The script to disable tcp chimney is :
netsh int tcp set global chimney=DISABLED