My dad and I have this ongoing argument about hard drives. He swears by Firewire and usually spends the extra dough to get what I used to consider to be nothing more than a nice logo and Apple-centric boasting rights. After my last LaCie tri-interface chassis crapped out a couple of years ago I began opting for whatever was cheapest at Staples, both for convenience’s sake and to try and save a few bucks. If you believe the marketing (and I used to), USB 2.0 is reallyreallyreally fast, faster even than Firewire. But, in fact, it’s not, and I recently learned the error of my ways.
A couple of weeks ago I decided to transfer and catalogue all of my old MiniDV camcorder footage into iMovie on my Mac. I’ve got about four-dozen tapes that date back to the 90s and I’ve begun to grow aware of the fact that their era is drawing to a close. It won’t be long before I’m stuck with 48 hours of valuable personal video that I can’t find a player for. So I figured a hard drive archive is my best option and I decided to commit a spare external 500GB USB 2.0 hard drive to the purpose.
I started transferring the footage using my old Canon Elura2 camcorder last week and all seemed to be going well. It wasn’t long before I noticed tons of dropped frames and even multi-second stretches of footage that failed to transfer. A lot of the audio was garbled and patchy digital static plagued too much of the footage. I’ll spare you the gory troubleshooting details but suffice to say I tested multiple cameras (even a brand new one), multiple cables, and different hard drives. The results were always the same: the video transfer was crap.
Then it hit me: my dad is right. And oh, how it chagrins me to admit it, but Firewire is superior to USB 2.0.
There are actually two USB 2.0 protocols. The vanilla “USB 2.0” supports a meagre data rate of just 12 mbps. On the other hand, “USB 2.0 High Speed” supports a peak data rate of up to 480 mbps. Compared to the original FireWire 400 protocol (which obviously supports 400 mbps data transfer) the latter USB 2.0 protocol would seem to be faster.
And it is, but only in peak performance. As far as a sustained data rate goes, USB 2.0 is much slower than Firewire 400, and its throughput degrades over time. In writing 300MB of files, Firewire is 33% faster than USB; but in writing 650 MB of files, the advantage grows to over 70% faster in Firewire’s favour.
This is due to the fact that Firewire devices have some intelligence built into them regarding how they manage data flow, so they are capable of maintaining a sustained rate of transfer. USB 2.0 devices, on the other hand, depend on an attached computer to inform them of how to manage the data flow; this constant back-and-forth communication degrades the rate of transfer over time.
This is not to say that USB 2.0 is a terrible protocol; it just has its use. If performance, such as with digital video streams, is a concern, then USB 2.0 is a no-go (as I’ve now well learned). For general desktop use, such as for file backups and small-file storage, USB 2.0 is adequate, especially when you consider the cost savings. However, to support the significant, steady data rates of a video stream, Firewire is a must.