This FAQ explains the factors that can effect switching speed for the ED.
This would have a lot of factors such as the TCP/IP stack on the PC network latency, how many retries the TCP protocol takes before it gets through and the time taken by the ED device to process the incoming TCP packet and to execute the correct command.
The actual chip we use switches on very quickly, in the micro-second to nano-second time frame.
Overall we know that the ED can process at least 200 commands a second from a PC on a lightly busy network. The latency is the order of the ping time to the ED device plus 5 milliseconds.