The popularity of flash drives has made USB storage ubiquitous. Thumb drives have effectively killed off the floppy, and perhaps before long, they'll push optical media out of the picture, too. Despite its convenience, the USB interface doesn't offer all that much bandwidth. Version 2.0 of the specification calls for transfer rates up to 60MB/s. In the real world, though, you're looking at less than 40MB/s. That may be much quicker than a floppy, but it's relatively slow for a modern PC. And slow transfer rates only get more annoying as storage capacities expand, encouraging users to transfer more and more data.

Help lurks just over the horizon in the form of a new USB 3.0 specification that promises to increase transfer rates up to 600MB/s. However, USB's third iteration isn't expected to be integrated into all-important Intel chipsets until 2011. There's no word on when it'll be included in core-logic chipsets from AMD or Nvidia, either, leaving would-be users to purchase add-in cards or one of a handful of new motherboards that offer USB 3.0 connectivity via third-party silicon.

So what about external Serial ATA? eSATA ports have slowly become common on even mid-range motherboards, and they've even popped up in a few laptops. The interface is plenty quick, too, offering transfer rates up to 300MB/s. But eSATA is just a data pipe, so it can't provide connected drives with power. That has to come from an external source, which has typically involved bulky power adapters for eSATA enclosures that plug into wall sockets. Auxiliary cables are cumbersome at best, and they're certainly not appropriate for pocket-sized flash drives.

Fortunately, a better solution exists. A hybrid eSATA/USB connector has been developed that elegantly melds USB and external Serial ATA plugs.

The hybrid eSATA/USB connector

If you think about it, the two interfaces are really a perfect match. A single USB port can already power the wealth of thumb drives on the market, and it can even handle most external 2.5" mechanical hard drives. eSATA brings ample bandwidth to the table, and with recent SATA controllers supporting hot-swapping, there's no need to restart your system to connect a drive.

You don't have to wait for hybrid eSATA/USB, either. Ports can already be found on several new P55-based motherboards from Gigabyte and MSI. Drives that use the technology are available, too. The first one we've seen is a Kanguru e-Flash thumb drive that comes with both USB and hybrid interfaces. It's currently selling in 32 and 64GB flavors for $114 and $190, respectively. That sounds expensive, but it's actually quite reasonable considering the prices of other high-capacity flash drives. And this one's a heck of a lot faster.

I plugged the e-Flash into USB and hybrid ports on a Gigabyte GA-P55M-UD4 motherboard and ran HD Tach's full disk test to get an idea of the drive's performance under Windows 7. When plugged into the USB port, the e-Flash achieved burst speeds of 37MB/s, sustained 36MB/s reads and 24MB/s writes, and consumed just 4% of the system's CPU time. On the hybrid connector, burst rates jumped to 84MB/s, sustained reads climbed to 67MB/s, writes increased to 32MB/s, and CPU utilization remained at 4%.

While the e-Flash doesn't come close to the peak theoretical bandwidth offered by the hybrid connector's eSATA component, the drive still offers double the read speeds and 33% faster writes than a typical thumb drive—and with seemingly zero penalty. I didn't even need to run the hot-swap application that comes loaded on the drive. Windows 7 handled the e-Flash much like a standard USB device.

With the exception of a slightly longer casing to make room for a second plug, the e-Flash is really no larger than your average thumb drive. It's a featherweight at just 22 grams, and measures an easily pocketable 89 x 24 x 7 mm (3.5" x 0.94" x 0.28"). The drive may not look terribly exciting, but it does have a thin-wall aluminum housing with a matte finish that doesn't attract fingerprints or smudges. The drive feels surprisingly solid for something so light, and the caps for both plugs fit nice and snugly. My only complaint about the casing is that it doesn't have an anchor that can be used to attach the drive to a keychain.

Of course, there's also the issue of whether your system has a hybrid eSATA/USB port that can take advantage of the drive's performance. Kanguru thought of that, though. The e-Flash comes with a PCI back plate adapter and the necessary cables to transform any internal Serial ATA port to an external hybrid connector. Power comes from a four-pin Molex plug, so you don't have to give up a USB port. Kanguru even throws in an extension cable to bring the hybrid connector out from behind the back of the system.

The adapter kit is a perfect addition to the package, making it easy to recommend the e-Flash to anyone looking for a faster flash drive than existing USB-based products. This little thumb drive also has me quite bullish on the future of the hybrid connector. The interface is perfect for high-performance thumb drives and even better for external 2.5" hard drive enclosures. With ports easily added to existing systems, hybrid eSATA/USB looks to be the best external storage interface to tide us over until USB 3.0 sees widespread adoption.