Most modern Macs, except for the MacBook Air and some MacBook models (such as my late 2008 unibody, alas), offer both FireWire and USB connections, so when shopping for an external hard drive you have plenty of options for something that will work with your Mac, notes Macworld’s James Galbraith. And these days, he adds, USB hard drives are more common and less expensive than FireWire or even FireWire/USB combo drives.
True, but even though USB 2.0 has a maximum theoretical bandwidth of 480 Mbps, vs. a nominal 400 Mbps for FireWire 400, via real-world experience I can attest that USB 2.0 lags well behind FireWire 400 — to say nothing of the FireWire 800 used on all Macs still sold today with FireWire support. And adding insult to injury, USB 2.0 doesn’t support incredibly useful Target Disk Mode. I’ve also found that while booting a Mac from a USB 2.0 drive is possible, it’s not nearly as satisfactory and low-hassle (or speedy) as booting from FireWire drives.
My gut-level impressions are borne out by Macworld’s lab testing, which found, for instance, that with a Western Digital My Book Studio 2TB Western Digital My Book Studio drive connected to a MacBook Pro, copying a 1GB file took 23 percent less time over FireWire 400 than over USB 2.0, while duplicating that file using FireWire 400 on the WD drive took 10 percent less time than when run over USB 2.0, and that FireWire 800 proved 35-58 percent faster than USB 2.0 in various tests on the MacBook Pro with the My Book Studio. Similar comparative results were noted using a compact Verbatim portable drive with the MacBook Pro.
However, the report also notes that the imminent release of USB 3.0 products in early 2010 promises speeds greater than FireWire 800 or even eSATA, but suggests that it may be some time before Apple begins supporting USB 3.0 with compatible ports (which will be backwards-compatible for USB 1.1 and 2.0 devices on Mac systems).
In the meantime, even a USB 2.0 only external hard drive is the best choice for a backup medium for most of us, especially using Time Machine in OS X 10.5 and 10.6 But my recommendation is to spend a few more dollars if necessary and get an external drive with multiple I/O interface support. Quad interface drives are becoming quite popular, able to handle USB 2.0 (and hopefully soon USB 3.0) plus FireWire 400, FireWire 800, and eSATA interfaces.
What’s your favorite backup medium and I/O interface?