ASYNC_NETWORK_IO usually doesn't mean that you are waiting on the network. It usually means that the application is processing the data one row at a time or simply doesn't acknowledge the receipt of data. Have a look at this blog on how to troubleshoot this wait type: http://blogs.msdn.com/b/joesack/archive/2009/01/09/troubleshooting-async-network-io-networkio.aspx