WD My Book Duo review: Fast, versatile, and affordable

If your computer has USB 3.0, the WD My Book Duo is an excellent external storage device if you need lots of extra storage space and fast performance on a budget. Here's CNET's full review.

Dong Ngo

Dong Ngo

SF Labs Manager, Editor / Reviews

CNET editor Dong Ngo has been involved with technology since 2000, starting with testing gadgets and writing code for CNET Labs' benchmarks. He now manages CNET San Francisco Labs, reviews 3D printers, networking/storage devices, and also writes about other topics from online security to new gadgets and how technology impacts the life of people around the world.

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There's much to like about the new WD My Book Duo desktop external storage device.


WD My Book Duo

The Good

The WD My Book Duo has plenty of storage space, fast performance, hardware RAID, and a built-in two-port USB 3.0 hub. The external storage device is also affordable, and allows you to easily replace its internal hard drives.

The Bad

It has a short two-year warranty.

The Bottom Line

The WD My Book Duo is a fast, versatile, and secure way to add lots of storage space to your desktop computer without digging a hole in your pocket.

For one, it's the first desktop external drive I've seen that comes with a built-in USB hub with two USB 3.0 ports. It also has hardware RAID, you can replace its internal hard drives easily, and it has a lot of storage. Finally, it delivers fast performance, especially when working in RAID 0, and it all comes at the affordable street price of just $280 (£250 in the UK), $350 (£315), $450 (£420), and $700 for 4TB, 6TB, 8TB and 12TB, respectively. (Australian pricing was not available at time of writing.)

If you can live with the short two-year warranty, the WD My Book Duo is an excellent USB 3.0 external storage device for your desktop computer, be it a Windows or a Mac. For other options, check out this list of top desktop external hard drives on the market.

The WD My Book Duo comes with two WD Red hard drives on the inside. Dong Ngo/CNET

Smart design with built-in USB hub

Taking the shape of a a closed book that's standing up, the WD My Book Duo is similar to the WD Thunderbolt Duo though with a few major differences. On the outside it uses USB 3.0 instead of Thunderbolt. And on the inside, it houses two WD Red internal hard drives instead of WD Green hard drives.

(The WD Red drive is made mainly for NAS servers, and has been one of the most reliable internal hard drives on the market. I personally use a lot of them and haven't had any failure to date.)

You can replace the two hard drives easily thanks to the lid on top that pops up with just a push -- no tool is required. WD recommends that you use the WD Red, but the My Book Duo supports any standard SATA hard drives.

Drive type Desktop external USB RAID storage system
Connector options USB 3.0, USB 2.0
Available capacities 4TB, 6TB, 8TB, 12TB
Capacity of test unit 8TB
Dimensions (LWH) 6.2 x 6.5 x 3.9 - inches (9.9 x 9.9 x 16.5 cm)
Weight 5.1 lbs (2.2kg)
OSes supported Windows XP or later, Mac OS 10.4 or later
Software included WD SmartWare Pro (Windows), Acronis True Image (Windows), WD Drive Utilities (Windows / Mac), WD Security (Windows / Mac)

On its back, the My Book Duo has one micro-USB 3.0 B-female port for connecting host computer via the included foot-long USB cable. In addition, it also has two USB 3.0 A-female ports, which you can use to connect an additional two USB devices to the host computer. That's a great design feature since the My Book Duo actually adds two more USB ports instead of taking one away. I tried the two extra ports with a few portable drives and they provided enough juice to power all of them.

The My Book Duo shares the power status with the host computer. That means that it automatically puts itself in the same state as the computer, be it shutdown, sleep, or on. Most Thunderbolt devices have that feature, which is much better than the drive going to sleep on its own. Also, with this smart design, the My Book Duo is always available to the host and saves energy based on how you customize the energy-saving feature on your computer.

The new storage device adds two extra USB 3.0 port to the host computer. Dong Ngo/CNET

Versatile RAID, helpful software

Out of the box, the two internal hard drives of the My Book Duo are configured in RAID 0 for maximum performance and storage space. RAID 0 has its own weakness; if one of the drives fails, you lose data on both. For important data, you should switch to RAID 1, which protects data against a single drive failure. You can change the RAID configuration by using the included WD Drive Utilities software, which also allows for drive diagnostics, erasing, and formatting. Note that switching the RAID configuration means that all existing data on the device will be erased.

The My Book Duo supports RAID natively, meaning that it doesn't rely on the host computer's operating system for its RAID configuration. This allows the drive's RAID configuration, once set up, to work on different platforms without having to reconfigure it.

The My Book Duo comes preloaded with a few helpful applications. Apart from the WD Drive Utilities, there are also WD SmartWare, WD Security and Acronis True Image WD Edition. If you delete these from the My Book Duo by accident, you can always download them from WD's website.

WD Security enables you to turn on My Book Duo's 256-bit AES hardware encryption, which keeps data from prying eyes in case of loss, and WD SmartWare is a very handy backup application. SmartWare can automatically detect and back up user-generated data or make backups of files and folders you choose. It then makes those backups based on a preset schedule or each time it detects changes. The only thing SmartWare can't do is back up the entire system for restoring in case the computer's main drive fails. That's why WD includes Acronis True Image WD Edition, which is excellent software for making backup images of an entire system.

Fast performance

I tested the My Book Duo with USB 3.0 in both RAID 0 and RAID 1 and it was impressively fast, considering that the WD Red hard drive is generally not tuned for high performance.

With RAID 0 the storage device registered a sustained real-world copy speed of 117MBps for writing and 211MBps for reading. When switched to RAID 1, it scored 110MBps and 150MBps for writing and reading, respectively.

With these numbers, among all USB 3.0 storage devices I've seen, the the My Book Duo is easily one of the fastest.

CNET Labs' USB 3.0 external drive performance

Seagate Backup Plus FAST (RAID 0) 222.5 232.74Brinell Drive SSD 156.4 220.2WD My Book Duo (RAID 0) 116.7 210.96Seagate Backup Plus Desktop 150.9 180.45WD My Book Duo (RAID 1) 110.3 149.89Toshiba Canvio Slim II 118.8 118.49WD My Passport Ultra 118.5 117.87Seagate Slim 110.4 111.49LaCie Christofle Sphere 105.5 111.43ioSafe SoloPro G3 109.1 110.8Seagate Backup Plus 90.94 110.1WD My Password Slim 107.7 107.89
  • Write
  • Read
Note: Measured in megabytes per second

The WD My Book Duo also worked with USB 2.0 in my testing with a speed of around 35MBps. That said, you do need USB 3.0 to take advantage of its performance.

In all, the My Book Duo worked well in my testing, without any hiccups, and remained cool and quiet the entire time.


The WD My Book Duo is a convenient and affordable way to add a huge amount of storage space to your desktop computer. Its fast performance means you can use it either as a backup drive or one that hosts hot data for heavy media-editing tasks. While it's not as fast as solid-state-based or Thunderbolt external storage devices, it's much cheaper and has so much more capacity. And the current street pricing makes it a much easier choice.

On top of that, the bundled software is such a helpful extra, possibly enough to make up for the short two-year warranty. Just make sure your computer supports USB 3.0 before getting it.


WD My Book Duo

Score Breakdown

Setup 8Features 9Performance 8Support 6