Portable External Hard Drive Roundup
Posted 03/26/2009 at 9:43am
| by Stephan Somogyi
Hard Drives
Hard
drives remain the leader for storage and speed versus size. While
flash-based USB drives remain the tiniest drives out there, physical
size isn’t everything. Hard drive makers continue to put a lot of
R&D into raising performance and increasing storage density:
Putting half a terabyte in a 2.5-inch laptop drive was unthinkable not
that long ago, and we reviewed a bunch of 500GB as well as some 320GB
drives, all based on spinning platters—no SSDs here—all of which are
thoroughly portable and run solely on the power delivered over USB or
FireWire.
How We Tested
Time is the scarcest
resource we have, so it made sense for us to focus on the speed of the
drives in this roundup. To test the drives’ performance, we created a
fresh install of Leopard with all the latest updates and turned this
volume into a disk image that could be easily restored with Apple
Software Restore (ASR), which is built into OS X. We then built a
custom tool that performed this task three times on each drive, which
allowed us to average the test results. This gave us a more
representative sense of each drive’s overall performance. ASR can run
in two modes: block copy, which is the fast option, and file copy, the
slow one. We set things up to use block copy, since it pushes data at a
drive as fast as possible.
Our test system was an 8-core Mac Pro, so
plenty of processor performance was available. Each run of the test
included the restore,
which writes the data to the drive being tested,
as well as a verify,
which reads it all back to make sure that data
integrity wasn’t compromised in the process.
In the real world,
users perform far more reads than writes on a typical hard drive, so
using a 1:1 ratio of read:write in a benchmark
isn’t realistic.
However, this ratio isn’t that far off for a drive used
for Time
Machine backups or for sneakernet. For this reason, we
feel this
benchmark methodology fit this particular collection of
drives well.

LaCie

500GB Rugged Hard Disk USB, FW800, FW400
LaCie www.lacie.com
PRICE: $279.99
REQUIREMENTS: USB, FireWire 400 and/or FireWire 800 ports
Physically robust. Difficult to lose due to bright-orange color.
Average performance. Comparatively large size.

Click link for full review
500GB Rugged Hard Disk USB
LaCie www.lacie.com
PRICE: $219.99
REQUIREMENTS: USB port
Physically robust. Difficult to lose due to bright-orange color.
Average performance. Chunky form factor.

Click link for full review
LaCie

LaCie 120GB Little Disk
LaCie www.lacie.com
PRICE: $199.99
REQUIREMENTS: USB port
Small. Capacious for its physical size.
Slow for a hard drive

Click link for full review
Other World Computing

320GB Mercury On-The-Go Pro Triple 7,200 RPM
Other World Computing www.macsales.com
PRICE: $179.99
REQUIREMENTS: USB, FireWire 400, and/or FireWire 800 ports
Cool case. Fastest 7,200rpm drive we tested.
Metal heat sink on drive’s bottom can scratch surfaces.

Click link for full review
320GB Mercury On-The-Go Pro Triple 5,400 RPM
Other World Computing www.macsales.com
PRICE: $149.99
REQUIREMENTS: USB, FireWire 400, and/or FireWire 800 ports
Cool case. Solid performer.
Metal heat sink on drive’s bottom can scratch surfaces.

Click link to for full review
Seagate

500GB FreeAgent Go For Mac
Seagate www.seagate.com
PRICE: $239.99
REQUIREMENTS: USB, FireWire 400 and/or FireWire 800 ports
Fast. Large capacity. Well designed.
Thicker case than the USB-only version due to the height of the FireWire 800 port.

Click link for full review
500GB FreeAgent Go
Seagate www.seagate.com
PRICE: $199.99
REQUIREMENTS: USB ports
Amazingly slim. Great design.
USB only.

Click link for full review
320GB FreeAgent Go For Mac
Seagate www.seagate.com
PRICE: $189.99
REQUIREMENTS: USB, FireWire 400 and/or FireWire 800 ports
Fast. Well designed.
Thicker case than the USB-only version due to the height of the FireWire 800 port.

Click link for full review

Toshiba

Toshiba 400GB USB 2.0 Portable External Hard Drive
Toshiba www.toshiba.com
PRICE: $179.99
REQUIREMENTS: USB port
Toshiba is a trusted name in hard drives.
Poor performance.

Click link for full review

Western Digital

500GB My Passport Essential
Western Digital www.wdc.com
PRICE: $199.99
REQUIREMENTS: USB port
Fastest USB performer.
USB only.

Click link for full review

500GB My Passport Elite
Western Digital www.wdc.com
PRICE: $219.99
REQUIREMENTS: USB port
Fastest USB performer. Sliding USB cover.
USB only.

Click link to read full review

500GB My Passport Studio
Western Digital www.wdc.com
PRICE: $249.99
REQUIREMENTS: USB, FireWire 400, and/or FireWire 800 ports
Fastest USB performer.
Poor FireWire performer. Thick case.

Click link to read full review

Drive Performance at a Glance
Speed isn’t everything, of course, but it’s a huge factor in any external storage buying decision.

Click image to enbiggen
Reads vs. Write
When looking at a drive’s performance, you want to pay closer attention to its read speeds, since most users perform more reads than writes to a typical drive. Bars show read and write times, in seconds,
for the set of drive tasks described
in “How We Tested”. NOTE: SHORTER BARS ARE BETTER/FASTER.

Click image to enbiggen
USB vs. FireWire—Speed and Power
Look at any
spec sheet for a USB device and it will usually proclaim that it
supports high-speed USB 2.0 at up to 480 megabits per second. Contrast
that with FireWire, which comes in 400- and 800-megabits-per-second
flavors, and you might assume that USB performs somewhat better than
the former and not as well as the latter. Well, you’d be wrong, and
we’ve got the test data to back it up.
FireWire was designed from
the outset to provide high-performance data transfer between devices,
but at the cost of having to put more intelligence inside each device,
which raised per-device cost. USB, on the other hand, was designed so
that the external device could be built as inexpensively as possible,
leaving all the smarts inside the computer. This decision, which puts
much of the transfer burden on the computer rather than the device,
also results in a measurable loss of performance. Most applications
that use USB today—keyboards, mice, or audio devices—don’t bump up
against the USB performance ceiling. But USB mass-storage devices, such
as external hard drives, definitely do. As our test results show, USB
does the job, but it’s much slower than even FireWire 400. This is
particularly noticeable with the drives we tested that have both
FireWire and USB: USB lost the race every time.
It’s Got the Power.
Back
in the early days of FireWire, it had one irrefutable benefit over USB:
delivering enough power to keep a hard disk going. FireWire can deliver
up to 45 watts of power, which is plenty to start a drive’s platters
and keep them spinning. The USB spec, in contrast, provides 500mW for
so-called low-power devices and 2.5W for so-called high-power devices.
While 2.5W previously couldn’t power very much, today’s laptop-grade
drives are so thrifty with their electrons that a USB port’s worth of
electricity is enough to run a hard drive. Some USB ports have had
difficulty delivering enough juice and, as a result, some drive
manufacturers have taken to providing Y-cables with their drives: One
USB connector for both power and data, and a second to supply an
additional port of power. The downside is that this uses up two USB
ports on your computer—and many laptops these days only have two to
start with.
USB remains more ubiquitous than FireWire, and even
Apple has decided that unless you’re a MacBook Pro or Mac Pro owner,
you don’t need FireWire anymore, which is a shame, since the
performance difference is pretty significant.
USB 3.0 SuperSpeed and Future FireWire.
Just
as this article was going to press, the USB Implementers Forum—the
trade group behind USB standards (www.usb.org)—announced USB 3.0, aka
USB SuperSpeed. USB 3.0 is supposed to provide throughput of up to 4.8
gigabits per second, a hefty 10x speed bump over the USB 2.0 spec. Not
only that, but USB 3.0 is also slated to deliver 10.8W of power,
another substantial increase. USB 1.0 and 2.0 devices will be
backward-compatible with USB 3.0 ports, which is good news for anyone
who likes to keep their older Macs and Mac peripherals around as long
as possible.
In contrast, FireWire 1600 and 3200, which offer
throughputs of 1.6 and 3.2 gigabits per second, respectively, were both
approved as IEEE standards in July 2008. Both of these higher speeds
use the same physical connector as FireWire 800, and are also
backward-compatible.
It seems likely that FireWire 400 has
reached the end of its life, and while FireWire 800 looks to be
significantly inferior to USB 3.0 on paper, our experiences with USB
2.0 compared to FireWire 400 lead us to reserve judgment on FireWire
1600’s and 3200’s viability until we can compare them to the first real
USB 3.0 devices, which are expected to start shipping in late 2009 or
early 2010.