We know that in general FireWire-connected hard disk drives have faster data transfer rates than USB-connected drives. That’s what we always hear at Apple’s Discussions except we have never seen actual numbers compared. If true, how faster are FireWire-connected hard disk drives, anyway? Those questions must have been raised 8 or 9 years ago. But let’s revisit this topic again. Another question that you may have is whether or not USB-connected hard disk drives are so bad that one should avoid buying them.

Screenshot 01 – Source: coneco.net

Screenshot 02 – Source: coneco.net

USB-connected hard disk drives are a lot cheaper than FireWire-connected ones. There’s a good Japanese website called coneco.net where you can compare prices of electronics products. Let’s look up 320 GB drives. The cheapest USB-connected drive that we find is Maxtor OneTouch III USB 2.0. (See Screenshot 01.) The price is 7,980 yen. It’s about US$74. And the cheapest FireWire-connected model for 320 GB drives is Maxtor OneTouch III Firewire 400 / USB 2.0. The price is 13,000 yen. It’s equivalent to US$120.40. (See Screenshot 02.) 

We have one FireWire-connected and one USB-connected hard disk drives each. We have another hard disk drive that has both FireWire and USB connectors. Comparing these three external drives, there is a major difference between FireWire-connected and USB-connected hard disk drives. If you drag and drop the icon of a FireWire-connected hard disk drive to the trash can, the drive will be ejected, and the motor of the disk drive will stop. Without turning off and on the power, you can still mount the same FireWire-connected drive to the desktop, using Disk Utility. If you launch Disk Utility, the computer will access the ejected FireWire drive. So if you select the ejected drive and press the Mount button, the drive will appear on the desktop. (See Screenshot 03.)

Screenshot 03 – Source: MacHouse

Screenshot 04 – Source: MacHouse

Screenshot 05 – Source: MacHouse

USB hard disk drives are different in this respect. Even after you drag the drive icon to the trash can, the motor of the USB-connected hard disk drive will continue to spin. The best you can do to make sure that the hard disk drive is ejected is to use, again, Disk Utility and unmount the drive. (See Screenshot 04-5.) But after doing so, the motor of a USB-connected hard disk drive will not stop spinning.

Screenshot 06 – Source: MacHouse

Screenshot 07 – Source: MacHouse

So let’s compare data transfer rates between FireWire-connected and USB-connected external drives. Again, we have one hard disk case that has both FireWire and USB connectors. (See Screenshot 06.) What’s installed in this hard disk case is an internal IDE 320 GB drive from Seagate. The data transfer protocol is 100. The buffer size and the number of revolutions (revolutions per minute) are 16 MB and 7,200 rpm, respectively.

As shown in Screenshot 08, we have one QuickTime file that is stored in the external drive labeled ‘Files.’ The file size is 2.12 GB. I just want to drag this file onto a folder belonging to an internal hard disk drive to measure data transfer time. (See Screenshot 09.)

Screenshot 08 – Source: MacHouse

Screenshot 09 – Source: MacHouse

Screenshot 10 – Source: MacHouse

Results are shown below. Not surprisingly, the FireWire connection is about 2.47 times faster in transferring data. Actually, we didn’t expect that there would be such a big difference.

As shown in Screenshot 10, we also copied 2 AVI files (1.37 GB) stored in the internal drive onto the external drive and measured data transfer time with two different connections.

The write speed is about 2.27 times faster with FireWire.

Okay. Again, these results aren’t so surprising. Anyway, do they tell us to buy FireWire-connected hard disk drives? No, not at all. We use one USB-connected hard disk case storing a 160 GB IDE drive. This USB-connected hard disk case is cheap. It cost us only $30 or $35. We didn’t want to throw away the old internal drive that came with iMac after buying a new 250 GB internal disk drive. We seldom use this USB-connected disk drive, which stores files that we are likely to use only once in every 3 to 6 months.

We use the FireWire-connected hard disk case in a totally different way. We use this drive just as if it were an internal drive. We use it to store local files. The internal disk drive is divided into 2 partitions, one for system and the other for application files. Because we compress about 200 videos a year, we need a large storage medium. If it’s completely filled with files, we can just buy a new drive without reinstalling OS and applications.

By the way, which is better, a stand-alone FireWire external hard drive drive and a FireWire-connected hard disk case with an ATA drive inside? We definitely recommend people to use FireWire-connected hard disk cases. That’s because if you run out of space on an existing ATA drive inside the case, you can just buy a new one. If the hard disk drive dies for any reason, you can still use the hard disk drive inside with a new case.