I'm using a sample UDP program to time reading a packet and I get around 12ms per 1k chars. I've had similar results with Uno. I got Due (and R3 ethernet shield) hoping the bottleneck in reading data was the processor speed but it seems unchanged. Is there a way to speed it up? Maybe upcoming ethernet board? Or Wi-Fi?
My arudino is controlling xmas lighting in remote location and is controlled by computer program. USB or serial cord, even a very long one, is not very practical.