My iMac 20" (Core Duo Intel Mac) has Firewire 400 ports, and USB ports. No Firewire 800 or eSATA ports.

While the theoretical limits of eSATA are extremely high, in reality it's faster than Firewire 800, anywhere from the same speed to about 35% faster depending on what test you look at. I was wondering how my interfaces compare for speed so I did a little test.

My home network includes my iMac and a Windows XP Media Center 2005 computer. These two computers are connected via (2) 100' ethernet cables and a NetGear gigabit router.

I wanted to see how fast my Firewire 400 external drives compared to saving files over the gigabit ethernet network to my Media Center computer. I also ran my external drives in USB2 mode just out of curiosity, I don't ever run my externals via the USB2 interface, I only did this for a comparison.

There is a certain amount of overhead in moving files, so I ran the speed tests on a single large file, and then next test was on thousands of small files.

Here are the results of the single 3.83GB file transfer:

The gigabit ethernet connected drive actually tied my external Firewire 400 external drive to the second. This rather surprised me, I just assumed a locally connected harddrive would be much faster than what is essentially a NAS drive connected via gigabit ethernet. While the Gigabit and Firewire 400 drives each took 165 seconds to complete the transfer, the USB 2 connection took 280 seconds. In other terms, the Gigabit and Firewire 400 connections moved the data at an effective 23.77 megabytes per second, while the USB 2 connection moved the data at an effective 14.00 megabytes per second.


The next test was moving 3,114 jpg files which was 2.21GB:

This time the Firewire 400 drive took a slight advantage over the gigabit ethernet connected drive, and the USB 2 drive still lagged considerably.
The Firewire 400 drive moved data at 19.67 MB per second.
The Gigabit ethernet drive moved data at 18.55 MB per second.
The USB 2 drive moved data at 11.61 MB per second.


You can see there was a lot of overhead in moving thousands of files versus a single file, here's how the three interfaces transfer speeds were reduced with the overhead of more files to deal with instead of 1 large file:

Transfer rate slowed down by:
Firewire 400 17%
Gigabit 22%
USB 2 17%
The external drive slowed down by the same percentage regardless of being connected via Firewire 400 or USB 2, the gigabit connection suffered a little worse with the overhead, but still turned in very respectable transfer rates and nearly equaled the Firewire 400 connection.

This tells me that if you like a clean and quite setup, a NAS box or Ubuntu file server in your closet, connected to your Mac via gigabit ethernet will offer you very respectable transfer speeds. Firewire 800 and eSATA are even faster, and the gigabit wouldn't compete with them, but many of us don't have those as an option anyway.



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