You will often find these initial timings are inaccurate and become more so as parts of the file get copied.
The actual time taken will depend on the available network bandwidth (10Mbit, 100Mbit or 1000Mbit wired, wireless etc) and usage on the host/client.
I have successfully transferred a 6Gb video file between two XP machines over 100Mbit ethernet with a crossover cable in 45 minutes, for a comparison.
John