Time for a geeky post, just because we wound up getting experimental and had a bit of fun with copying files around, though I admit that probably doesn't sound like much fun.

So you've got a bunch of digital pictures to transfer from one computer to another, movies, a pile of music, anything like that. In our case it was 21.7GB and so the question arose of whether to transfer via hard wired ethernet or via file copy to USB external drive. If you like a trivia game, you can answer now ____ and then read on for the result. My initial thought was USB, except that we would need to copy twice, once to get it onto the external HD and then again to get it off, and the two operations combined might exceed ethernet speed.

First up was to try via the network, and in this case that is with fast ethernet or 100Mbit/s. We will also have a go with gigabit because a spare switch happens to be at hand.100Mbit ethernet we took 32 Minutes at a transfer speed that fluctuated very little between 11.1-11.2 MB/sec.

Next up we snapped in a gigabit switch and did it again. This time we copied the files across in 8 min! at a speed that fluctuated between 40.9 - 47.6 Mbit/sec. It was interesting that the speed varied so much more over gigabit. I put this down to the hardware being fully able to keep up with the fast ethernet connection, so the ethernet speed itself was the limiting factor. Whereas with gigabit, there is enough capacity that the transfer is affected by other hardware components inside the PC. Dell Precision workstation on both ends, btw. Notice that the fast ethernet transfer takes place very close to the theoretical maximum transfer speed of approx 12 MB/sec whereas the gigabit transfer is considerably lower than than its max transfer speed of some 120MB/sec.

And then for the USB...

While the initial file copy dialog popped up with an eye popping 105MB/sec this would prove well too optimistic. After the transfer settled down, this would eventually decline to a much steadier 26.7MB/sec and we would finish out with all files copied at the 15 min mark. That's copied once, with a duplicate needed on the other end.

During this 15 min I had enough time to consider that not all USB ports are equal, and I learned something here, and that is that by drilling down into the device manager, you can go into the Properties on each USB port, on the Advanced tab, and actually see if you are transferring at "high speed" or the not-so-delightful "full speed." Indeed this PC has an abundance of ports both front and back, and it did have some of each. But the one I was using was in fact high speed.




So the moral of this story, reader, if you have made it this far, is with gigabit ethernet you can dispense with the USB drive and just transfer your files across the network. And with fast ethernet it is going to be a close race, enter lots of caveats about network contention and YMMV, etc, but this was our outcome, on this day.