Actualy there is also UDP and VI server to consider as a transfer method...
I'm attaching a presentation given by NI. It focuses on transfer of data from LV-RT but the principles apply the same to LV6i. Start reading at
PAGE 18 since that is where it talks about transfering data over Ethernet.
As you will see, the RAW tcpip functions in LV are the fastest however with smaller data packet sizes.