The Need for Speed
Nov 24, 2010 12:00 PM, By Dan Ochiva
Will FireWire die now that USB 3.0 delivers?
Most of us don't worry about the time it takes to do a single file transfer, such as reading in a backup file from an attached drive. Running over a standard USB 2.0a common connection for backup drivesyou'll get anywhere from 14MBps to 40MBps transfer speeds.
Why the big range? USB 2.0 relies on the host computer's processor to oversee the actual transfers, so a CPU might have to contend with other computer chores at the same time.
There are other reasons to be wary of folks claiming the real numbers on throughput speeds: There are any number of variables, with some reviewers claiming you should only use empty, newly reformatted drives to do your tests, while others claim that you can't get real-world results without using disks that are already partially filled with the type of files you'll be working with on a regular basis.
So take the following numbers as guides, not givens.
Figuring that a standard transfer speed for USB 2.0 runs around 35MBps (see this ExtremeTech page for more on that), you can expect to spend around 30 seconds to read a 1GB file to your computer's drive.
Not so bad. But if you're an editor who works daily with similar-sized or larger files, that's a pokey rate. You're smart, so you've long ago moved to other, speedier connection technologies.
Mac users have championed FireWire for years, in both its initial 400 designation and the more recent 800 (both numbers refer to the top theoretical transfer speeds at megabit-per-second rates). FireWire delivers much higher throughput than USB 2.0. The main reason? It was designed with low CPU overhead (tech heads might say it's a highly efficient peer-to-peer, full-duplex, nonpolling data communications protocol) so it achieves throughput speeds much closer to its theoretical 800Mbps data rate.
FireWire turns out to be ideal for disk-intensive uses such as online editing. Since it doesn't need regular supervision from a controlling computer, it has become a favorite for simple transfers such as pulling in data from camcorders to a drive.
Real-world numbers? One top reviewer rates FireWire 800 as delivering sustained data transfers of around 54MBps (see this Tom's Hardware article for more), though another article quotes its results as closer to 74MBps. Again, read test numbers with the understanding that final results can vary greatly.
eSATA, or External SATA, came to market in 2004. Targeted for prosumers who were requiring more external storage for photos and music, as well as professionals who needed stable, fast storage connections, it has had some success in reducing typical interface bottlenecks, allowing fast hard drives to come close to their performance potential when located external to a server or PC.
Throughput speeds are comparable to FireWire 800, with caveats: Cable length is limited to around 2 meters, and, unlike FireWire, eSATA can't directly supply power to devices connected to the eSATA bus.
USB 2.0, however, has become near-ubiquitous for connecting external storage for backup. The electronics behind FireWire 800, while good in carefully controlled setups, are complicated to implement and expensive to boot. FireWire 400 still offers higher real-world transfer speeds over USB 2.0, while its ability to run power to sustain disk drives makes it ideal for simpler connections to disk arrays. But even Apple, FireWire's champion, now only includes a FireWire connector on its workstations and MacBook Pro line, foregoing it on the MacBook Air and MacBook.
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