To date all the hybrid storage solutions we have seen have been rather limited. Seagate got the idea right with the Momentus XT but having only 8GB of NAND (4GB in the first generation) limited the gains of caching dramatically. There simply wasn't enough NAND cache to fit all the data that users frequently used. Sure it was better than a traditional hard drive but the experience was far away from the real SSD experience. I'm actually surprised that there hasn't been any major evolution in the hybrid market -- the original Momentus XT was released over three years ago and fundamentally the current third generation Momentus XT is very similar. Back then I would've expected more and better offerings to be released within a year but obviously that hasn't happened. Until now.

WD Black2 combines a 120GB SSD and a 1TB 5400rpm hard drive into one 2.5" 9.5mm solution. WD doesn't actually call the Black2 a hybrid drive, but a dual-drive because the the SSD and hard drive are completely separate. In other words, the drive will appear as two separate volumes: 120GB SSD and 1TB hard drive. There's no caching involved and the end-user can decide what goes to the SSD as if it were a standalone drive. By default only the SSD portion is usable but WD supplies a USB drive with drivers in the retail package to make the hard drive portion visible to the OS as well. All Windows versions from XP and up are supported but there is no OS X support at the time of launch.

WD Black2 Specifications
Interface SATA 6Gbps
Sequential Read 350MB/s
Sequential Write 140MB/s
Power Consumption 0.9W (idle/standby) / 1.9W (read/write)
Noise 20dBA (idle) / 21dBA (seek)
Warranty 5 years
MSRP $299

The performance specs above are for the SSD part. Unfortunately WD wasn't willing to disclose any hardware details about the SSD other than that it uses 20nm NAND but we will find out the details once our review sample arrives this week. I was, however, able to get the information that WD worked with a partner to bring the Black2 to the market and that partner wasn't SanDisk (which was my first guess due to their prior partnership in hybrid drives). The actual hard drive spins at 5400rpm and consists of a single 1TB platter but WD didn't release any separate performance data for it. When the hard drive isn't in use, it can spin down to reduce power consumption, although 0.9W is still fairly high compared to most SSDs. 

Update: Techreport has already received their sample and opened it up, which revealed JMicron's JMF667H controller. We don't have any prior experience with the controller but generally JMicron's controllers have not been the greatest but it's been years since we've tested a JMicron based drive so things might have changed.

Update 2: WD initally told us that the drive is a single-platter design but they've now corrected their earlier statement. The hard drive consists of two 500GB platters as some of you suspected in the comments.

Given that most laptops only have room for one 2.5" drive by default, I do see a potential market for the Black2. In the past consumers have had to make the choice between a fast but small SSD or a large but slow hard drive. The Black2 eliminates the need to do that compromise. However, I'm disappointed for the lack of caching support. WD told us that they conducted market studies and according to those end-users wanted full control of the SSD and data. I don't completely agree because the reason why most consumers have negative thoughts about caching is because the available cache sizes are just way too small. Apple is the only one who has done it right with Fusion Drive by not going any smaller than 128GB, while others are trying to get by with 8-32GB. The Black2 has enough NAND for a pleasant caching experience, so not including caching software is a letdown. Technically you could use third party caching software but I still would have hoped for a solution from WD, preferably something user-configurable so it's not forced like in the Momentus XT.

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  • Gigaplex - Monday, November 25, 2013 - link

    Luckily this is targeted at enthusiasts and to a lesser extent OEMs. Casual consumers wouldn't look at something like this.
  • 6cef - Monday, November 25, 2013 - link

    1. they can charge a premium because laptop space is at a premium. if i only have drive slot, then i don't care that i can get an ssd for $80 and a hdd for $80, because i'd need to spend $1000 on a new laptop.

    2. the usb aspect of this is pretty weird, though if it ultimately works, it doesn't really matter.

    3. my laptop has one 2.5" slot & 2 msata slots. this would be useful if i wanted to setup the msata as raid 0 or 1, and still have another drive to put something like the page & hibernate file in windows, which on a laptop with a lot of memory can take up a lot of space. in that use case, top performance & reliability aren't a huge concern, because the data is basically transient anyway.
  • danwat1234 - Tuesday, December 30, 2014 - link

    The drive is down to $145 online now!
  • Teizo - Monday, November 25, 2013 - link

    Samsung 840 EVO + 1GB WD Black 1 TB = $200 and close to double the performance. This is a really good idea, but the price is horrible and only someone with a m-itx htpc would come close to touching this, and even then the 1 GB HDD would be pretty limiting for storage.

    Nonetheless, this is a really good concept. Now just to get performance on par with standalone SSDs and get the price competitive and they will have a hit.
  • kpb321 - Monday, November 25, 2013 - link

    I'm not sure if it will be a success but I do think that there is a market for a drive like this and for all the people comparing it to multiple drive setups for the cost and/or performance they seem to have missed it. There are a lot of laptops out there that only have 1 HD bay and no mSata or other slots so you have the choice of a fast SSD or a large HD. This tries to provide you both.

    The price premium does seem a little high and it probably would be nice if it included a software caching option too but ultimately I don't think either of those things changes the market it is targeted at. It is still significantly cheaper than a 1tb ssd.

    Sure, if you've got the option separate hd's or a hd and a mSATA then that is probably going to be cheaper and/or faster but a lot of laptops don't have that option and more people are using a laptop as their primary machines. My home desktop has a 120gb ssd and a 2tb hd but I'd definitely consider something like this or make a mSATA a high priority on my laptop purchase if I was looking for a laptop to use as my primary machine.
  • Bob Todd - Monday, November 25, 2013 - link

    Your point about mSATA or M.2 being in a minority of laptops is indeed true. There is a market for a 2.5" hybrid (or even combo like this) drive with enough NAND to store the entire OS/app selection on. But there are two huge problems here, the biggest of which is price that you have already mentioned. If this was $200 I think a very good argument could be made for it. The other problem is that it's a 9.5mm drive. So while I believe there is a good market for similar device, they've now cut that target market down into a fraction of the total addressable pie. I'd wager that a huge part of the market that wants a "bigger fast storage solution" that only has one 2.5" bay available would be satisfied with SSDs in the 500GB range. Those people are better served with something like a $300 512GB SSD. Then there's the part of the target market that has a single 2.5" bay that only accepts a 7mm height, which is quite a number of more recent thin and even not-so-thin laptops. I think each of its faults on their own aren't damning (price, height, non-caching/tiered firmware), but I believe the target market they are left with when you combine all of them is pretty tiny.
  • BigLeagueJammer - Monday, November 25, 2013 - link

    If it doesn't have caching I don't see the point except for a small niche. Most people don't want to have to think about where they put their data. I could see them putting it all on the SSD or all on the hard drive because it'd be easier to do it that way. Also, at that price you could buy a 500GB SSD.
  • Vinas - Monday, November 25, 2013 - link

    In sorry but the poor penmanship in this article made it uncomfortable to read.
  • Ryan Smith - Monday, November 25, 2013 - link

    The poor penmanship?

    Penmanship: the art or skill of writing by hand.
  • YazX_ - Monday, November 25, 2013 - link

    5400 RPM!!!! seriously

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