WD combines 120GB SSD with 1TB HDD in a laptop drive

Benchmark tests of WD's Dual Drive were less than impressive when compared with pure SSDs

Western Digital has unveiled its WD Black Dual Drive, which allows users to access ether a 120GB SSD for performance or a 1TB hard drive for archiving massive amounts of data.

Western Digital (WD) today released a laptop drive that combines a full-sized solid-state drive (SSD) with a 1TB hard disk drive, offering users high performance or high capacity storage through a single interface.

The company claims its WD Black Dual Drive is 17 times faster than a traditional hard disk drive and costs about three times less per gigabyte than an SSD. The new drive only works with Windows hardware and will retail for $299. The drive does not come as a stand-alone unit, but as a kit that includes installation instructions and hardware. It comes in a standard 9.5mm high, 2.5-in diameter form factor, and has a SATA III, 6Gbps interface.

The WD Black Dual Drive combines a 120GB SSD with a 1TB hard disk drive.

Desktop computers have offered dual drive slots for years, allowing users to install a low-capacity SSD for the OS and heavily used applications, and a slower, but much higher capacity hard disk drive (HDD) for mass data storage.

"This is a great solution for users that have only one slot," a WD spokesperson said in an email to Computerworld. They want the speed of the SSD and the capacity of the hard drive."

As with Seagate, WD was already selling a "hybrid" laptop drive (also called a solid state hybrid drive or just SSHD), which combines a small amount of NAND flash (SSD) with a traditional spinning disk. Like the new WD Black Dual Drive, WD's SSHD uses a 5400rpm spinning disk. The difference between the two drives is that the SSHD stores all data on the spinning disk and uses the SSD portion of its storage as cache to serve up frequently used data, such as the OS during boot ups and for apps when they're loading.

WD said its SSHD, which began shipping in April, was sold exclusively to computer manufacturers; the price of the WD Black SSHD was never released.

But it was WD's own laptop-maker customers who clamored for a new product to give consumers more control over where data could be stored.

"Our SSHD didn't allow them to optimize their speed and storage," said Melyssa Banda, WD's senior director of product marketing. "We're not controlling what goes where. Users have full control over where their data goes."

A spokesperson said WD has no plans to discontinue its existing SSHD drive in light of the new WD Black Dual Drive.

The new WD Black Dual Drive is an industry first in terms of capacity and functionality. As Banda said, users can control where data is stored -- on the SSD or on the spinning disk. With 120GB of SSD capacity, users can store not only the OS, but a large number of applications and files that they frequently use, such as games or streaming video. Data can then be archived on the hard drive portion of the disk.

By comparison, WD's Black SSHD comes with 8GB to 24GB of NAND flash memory on board, depending on laptop system manufacturer requirements.

Seagate, the first manufacturer to produce hybrid drives, has gone through several generations of its 7mm high laptop SSHD. That drive comes with 8GB of flash memory from Intel on board. Seagate also uses a 5,400rpm spindle speed hard drive.

In comparison to WD's new Black Dual Drive, a 1TB Seagate SSHD sells for about $120 on sites like TigerDirect.com.

Performance

SSD Performance Comparison Chart

The WD Black Dual Drive cannot be used in RAID environments, so it's not the proper drive for network-attacked storage (NAS) or storage area networks (SANs). However, if the spinning disk fails, the SSD portion of the drive will continue to work, according to Banda. The hard drive and SSD have separate controllers.

The WD Black Dual Drive comes with an installation kit that includes a USB to SATA cable, a USB thumb drive with installation software and an instruction manual

The WD Black Dual Drive uses 1.8 watts of power during read/writes and 0.9 watts while idle or in sleep mode.

According to WD's specification sheet, the SSD portion of the WD Black Dual Drive has a top read/write rate of 350MB/s and 130MB/s, respectively. That's well below many of today's SSHDs and SSDs.

For example, Samsung's least expensive 1TB SSD -- the 840 EVO -- has a read/write speed of 508MB/s and 488MB/s, respectively. The Samsung 840 EVO sells for about $500.

When you first install the WD Black Dual Drive only the SSD portion is activated. WD includes a USB stick in the drive kit with software to create the second partition for the hard disk drive.

So when I initially tested the drive, I was only testing the SSD's performance. I used a fresh installation of Windows 7 Pro on a Sony Vaio laptop running on an Intel Duo Core 2.26GHz processor with 4GB of RAM.

I used Atto Disk Benchmarking software for the test. The results were less than impressive with 269MB/s sequential read and 147MB/s write speeds.

Boot up time was 22 seconds. How does that compare? High-end consumer SSDs I've tested in the past sported boot ups 12 to 15 seconds. A less expensive SSD, such as the Samsung 840 EVO (a 250GB model sells for $200), had a boot up time of 25 seconds.

Shutdown was where the WD Black Dual Drive drive really shined; it took just five seconds. But, you also have to take into account that I was using fresh installation of Windows, with no applications running. Still, shutdown speed was impressive. A system restart took 34 seconds.

Lastly, I transferred a 2GB file on the Dual Drive. It took 20 seconds. This is twice the time it has taken with SSDs I've tested in the past.

Even if the performance was not up to that of a top-rated SSD, such as Seagate 600 or the Intel 520 Series, the WD drive is still easily three to four times faster than a hard drive, and it comes packed with 1.2TB of capacity. The highest capacity SSDs I've tested, and that are common on the consumer market, have 512GB or 256GB capacity -- well under half to a quarter of the Dual Drive's capacity.

Mark Peters, an analyst with research firm Enterprise Strategy Group, said the higher cost of the WD Black Dual Drive doesn't make sense for the mass market, given that a 1TB SSHD can be had for around $120.

"I think the obvious intent of this, given that it's persistent data in each case [the SSD and the HDD], is you have the benefits of speed and capacity," he said. "But, I still don't think the cost makes sense."

Peters envisioned the new drive being popular with high-end laptop users, video editors or gamers who may need the persistent speed of an SSD combined with large amounts of archival storage. "I think it will be a killer product for those who need it," he said.

Lucas Mearian covers consumer data storage, consumerization of IT, mobile device management, renewable energy, telematics/car tech and entertainment tech for Computerworld. Follow Lucas on Twitter at @lucasmearian or subscribe to Lucas's RSS feed. His e-mail address is lmearian@computerworld.com.

See more by Lucas Mearian on Computerworld.com.

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This story, "WD combines 120GB SSD with 1TB HDD in a laptop drive" was originally published by Computerworld.

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