Model: HornetTek Viper U3 USB 3.0 Hard Drive Enclosure
Manufacturer: HornetTek
Provided By: HornetTek

While a relatively new name in the United States, HornetTek has a history that goes back more than a decade. The company began manufacturing enclosures in 1999 and has established itself as one of the industry's leading enclosure providers, specializing in external storage and multimedia solutions. By forming a standard yet efficient product development procedure, HornetTek's engineering team is able to deliver state-of-the-art designs at a competitive price.

HornetTek recently released an updated version of its popular Viper 3.5-inch hard drive enclosure. The new Viper U3 retains the same simplistic design as the original. Made out of rigid aluminum, the enclosure's case applies catalytic heat dissipation mechanisms to remove heat and keep the hard drive cool. The Viper U3 also utilizes a vertical stand, minimizing the amount of space occupied. Last but not least, it features a SuperSpeed USB 3.0 interface capable of delivering transfer rates up to 5 Gb/s.

HornetTek Viper U3 USB 3.0 Hard Drive Enclosure

Model HT-316-U3J
Interface USB 3.0
HDD Support 3.5" SATA I/II/III HDD
HDD Capacity Supports up to 2TB
File Transfer USB 3.0 at 5 Gb/s max
USB 2.0 at 480 Mb/s max
Material Front and side aluminum with back ABS panel
OS Support Supports Windows 2000/XP/Vista/7, Linux or above and Macintosh OS 8.6 or higher



The Viper U3 comes in a stylish black box, similar to the ones HornetTek's other enclosures come in. The front, back and sides of the box show the enclosure from various angles and list many of its features. Inside, you'll find the enclosure as well as a small box of accessories. Along with an AC power adapter, HornetTek has included a USB 3.0 cable, vertical stand, user's manual and a bag of screws.



The Viper U3 shares the same basic design as the USB 2.0 and eSATA equipped versions of the enclosure. It measures 187 mm x 117 mm x 30 mm and weighs 353g without a hard drive installed. While the front and back of the Viper U3 are made of ABS plastic, the body is constructed of brushed aluminum. This not only looks great, it helps keep the drive inside cool.

Along the front of the Viper U3 you can see a pair of LED indicators. These two LED's light up blue when the unit is powered on and will flash to show disk activity. Sadly, these two LED's are not nearly as bright as what is portrayed on the packaging. On my Viper U3, they were so dim that I had a hard time determining whether or not the unit was actually powered on.

The rear of the Viper U3 is pretty straight forward. Below the USB 3.0 port, there is the main power switch and the enclosure's DC power connection.



Installing a hard drive in the Viper U3 is very easy. To begin, remove the two screws on the back of the enclosure and slide out the rear panel and inner tray.

The next step is to mount the hard drive to the tray. The easiest way to do this to place the hard drive on top of the tray and line it up with the SATA connectors on the backplane. Gently push the hard drive onto the connectors and then flip the tray over and screw it into place. I recommend using the screws that come with the Viper U3 as they are low profile and will not cause the tray to hang up on the enclosure.

With the hard drives installed, insert the tray into the enclosure and screw the rear panel into place. Once this is done, you can go ahead and connect the USB 3.0 cable, plug in the power cable, and turn the enclosure on. If everything goes as planned, your computer should automatically detect the Viper U3 and install any drivers it may need.




The test system used in this review was an HP dc7900. The computer came equipped with an Intel Core 2 Duo E8400 3.0GHz CPU, 2GB of DDR2 800MHz memory, Seagate Barracuda 7200.10 ST3250310AS 250GB SATA hard drive, NVIDIA Quadro FX570 256MB PCIe graphics card, Intel 82567LM-3 gigabit network card and Patriot SuperSpeed USB 3.0 PCIe host card. For the operating system, I installed a fresh copy of Windows 7 Enterprise.

To test the performance of the HornetTek Viper U3, I ran a series of benchmarks using CrystalDiskMark 3.0, HD Tach RW, ATTO Disk Benchmark 2.46 and HD Tune Pro 4.50. I used a Hitachi Deskstar 1TB 7K1000.B hard drive and ran the tests with the enclosure plugged into a USB 3.0 port and then again using USB 2.0.

CrystalDiskMark 3.0:

First, I ran a few quick tests using CrystalDiskMark. This benchmark tool measures the performance of a storage device by testing its sequential read and write speeds as well as its random read and write speeds using blocks 512K and 4K in size.

HornetTek Viper U3 - USB 3.0

HornetTek Viper U3 - USB 2.0

The Viper U3 performed very well when connected to the computer's USB 3.0 port. In our tests, the enclosure reached speeds as high as 116 MB/s when reading and 102 MB/s when writing.

HD Tach RW

Using HD Tach, we can benchmark a drive's read, write and burst speeds as well as its seek times and CPU usage.

When connected to the computer's USB 3.0 port, the Viper U3 had average read and write speeds of  93.2 MB/s and 93.7 MB/s, respectively, as well as a burst speed of 138.4 MB/s. The enclosure wasn't nearly as fast when using USB 2.0 though. Compared to what we saw with USB 3.0, the Viper U3's read and write speeds dropped by two-thirds.

ATTO Disk Benchmark 2.46:

I also used ATTO Disk Benchmark to test the Viper U3's sequential read and write speeds. The tests are run using blocks ranging in size from 0.5KB to 8192KB and the total length set to 256MB.

HornetTek Viper U3 - USB 3.0

HornetTek Viper U3 - USB 2.0

When tested with ATTO, the Viper U3's USB 3.0 read speeds topped out at about 115 MB/s and its write speeds at 97 MB/s.

Final Thoughts:

With the Viper U3, HornetTek has delivered a simple, yet functional hard drive enclosure that should meet the basic needs of most users. The Viper U3 is well constructed with an aluminum body that not only looks good, but acts like a heat sink to help keep your hard drive cool. The downside here is that it can get a bit warm to the touch. Thanks to its USB 3.0 interface, the HornetTek's new enclosure also offers some impressive performance. With USB 3.0 providing transfer speeds up to 5 Gb/s, the Viper U3 shouldn't have any problems keeping up with the industry's fastest SATA hard drives.

The HornetTek Viper U3 is available now and can be purchased from online stores like Amazon and for less than $35.


  • Well constructed
  • Great USB 3.0 performance
  • Compatible with Windows, Mac and Linux
  • Backwards compatible with USB 2.0
  • Includes vertical stand
  • Reasonably priced


  • LEDs are very dim
  • Can get warm to the touch
  • Doesn't support hard drives over 2TB in size