The theoretical improvement in throughput that USB 3.0 offers is certainly dramatic--a 10X jump to 5 gbps over the existing USB 2.0 spec, which maxed out at a theoretical 480 mbps.
But how does USB 3.0 fare in the real world? Pretty darn well, it turns out.
To determine the veracity of the USB-IF's claims, we ran four SuperSpeed USB 3.0 drives through our test suite, which includes batch operations on a large set of small files, transfers of very large files, and a virus scan test that emphasizes a hard drive's seek speed. Three models were 3.5-inch external desktop units: Buffalo's $200 DriveStation USB 3.0 HD-HXU3, Iomega's $240 eGo Desktop USB 3.0, and Western Digital's $200 My Book 3.0. The fourth drive was Seagate's $180, 2.5-inch, portable BlackArmor PS 110. (See our chart, which has links to the full test reports and specs.)
Three drives came formatted in the NTFS file system, which is more efficient than the FAT32 file system in which the Buffalo drive was formatted. (FAT32's only benefit is that both Macs and PCs can read and write to the drive.) Fortunately, Buffalo provides an option to reformat the drive as NTFS; we used it, and all of our test results reflect this.
In PCWorld Labs tests, the drives assessed using USB 3.0 consistently proved noticeably faster than when using FireWire 800 (by as much as a third). And we found the USB 3.0 drives to be comparable in speed with eSATA drives (over a SATA-300 interface); the eSATA drives typically edged out the USB 3.0 units on a couple of our performance metrics.
By comparison, USB 2.0 looked like a dog cart in the Kentucky Derby. Depending on the test, USB 3.0 proved to be up to 3.5 times as fast and always more than double USB 2.0's speed.
Of the three desktop-size models (each with a 3.5-inch hard drive inside), the Western Digital My Book 3.0 was fastest overall, with the Buffalo and Iomega drives finishing right behind it. The drives were separated by mere seconds on almost all of our read and write tests; we saw the greatest distinction on our malware scan test, with a span of 24 seconds between the fastest (Western Digital) and the slowest (Buffalo).
Portable drives always lag their desktop counterparts in performance, simply because of their slower rpm (rotations per minute) speeds. As such, it's no surprise that the portable Seagate BlackArmor PS 110 was not as fast as the desktop drives evaluated here. However, among the portable drives we've tested, this model leaped into second place; only the WiebeTech ToughTech XE Mini 500GB, tested over eSATA, bested Seagate's USB 3.0 portable.
In PCWorld Labs power consumption tests, we found that the average power draw at any given time for the USB 3.0 drives was slightly greater than that of USB 2.0 while data was transferring. However, since USB 3.0 does things far more quickly, multiplying the average draw over time shows it doing roughly twice the work per watt.
Beyond performance measurements, USB 3.0 has a huge edge in convenience over eSATA. Unlike eSATA, USB 3.0 was designed with removable storage in mind. It's hot-pluggable--you simply plug in a device, and your operating system quickly adds it to the list of available devices. By contrast, eSATA drives nearly always require a system reboot to appear.
Furthermore, since USB 3.0 is a powered port, you don't necessarily have to run another external power supply to the drive as you normally do with eSATA drives. Most 3.5-inch hard drives, however, require more power than the USB bus can deliver, and those models will still need AC adapters.
Certified USB 3.0
One of the things to look for when buying a USB 3.0 product is the certified SuperSpeed USB 3.0 logo--a label that will ensure that the product you're purchasing truly lives up to the new specification.
At this point, though, expect companies to release USB 3.0 products without official certification or the SuperSpeed logo. An example is the Buffalo Technology HD-HXU3, which was the first drive to market; and LaCie's drives, which are in the process of certification, will initially carry LaCie's own logo for USB 3.0 (the company says it plans to put a sticker on the products' box once certification is completed).
One good thing: This time around, you won't have to worry about whether you're really getting the promised speeds. In the transition from USB 1.1 to USB 2.0, the creators of the latter spec wrote it in such a way that products didn't have to communicate at the full 480 mbps in order to be called "USB 2.0." In contrast, for a product to be certified as supporting USB 3.0, it must operate at the full 5 gbps.
It's easy to upgrade to USB 3.0 on the desktop: You can buy adapter cards on the aftermarket for approximately $30, pay extra for a card from Buffalo ($70), or choose the Western Digital drive that includes a card (which carries a $20 premium over the version of the drive sold without the card).
With laptops, however, upgrading will be a tougher road. Unless your portable has an ExpressCard slot to accept an adapter such as the one that ships with the Seagate BlackArmor PS 110, you're not going to be able to add USB 3.0 to the notebook that you have now.
New laptops, though, will be a different story--eventually. So far only HP and Fujitsu have announced limited USB 3.0 support on laptops. Taiwanese laptop and desktop manufacturer MSI says it won't have USB 3.0 until the third quarter of this year, at the earliest. Product managers for both laptop and desktop makers cite manufacturing concerns such as having chipsets available in large quantities, and the need to test USB 3.0 chipsets, as reasons for the delay.
The Final Word
Speed, backward compatibility, power consumption...USB 3.0 more than lives up to the hype. It's only marginally slower than eSATA, and is far better suited to removable storage.
eSATA may yet pull farther ahead, especially once external enclosures built with 6-gbps SATA (SATA-600) come to market. However, now that USB 3.0 is here, we wouldn't be surprised to see eSATA lose traction to USB 3.0--at least in the general, non-high-performance consumer market. FireWire 800 is in a similar position: Aside from Mac support, FireWire 800 provides no tangible benefit over USB 3.0.
In the end, the real question is, do you want to have the speed of USB 3.0? We certainly do.