Western Digital Black² 1TB Dual Drive Hybrid Review
The continuing tug of war between performance-orientated SSDs and capacity-focused hard drives has created a demand for ‘hybrid’ solutions which allow consumers to experience the best of both worlds. That’s exactly what Western Digital is aiming to accomplish with their new Digital Black² Dual Drive solution. It’s a particularly innovative, unique take on the two issues that normally plague these hybrid solutions: a lack of NAND and very little customizability.
In order to understand why Western Digital is approaching these new drives from a different perspective, the current hybrid situation needs to be explained. The typical hybrid drive combines a relatively large but low speed spindle-based HDD with a few gigabytes of onboard NAND to boost performance. This NAND is set aside for caching purposes and works alongside built-in algorithms to “remember” your most-used programs by keeping the necessary boot files in quick-access storage. However, since the amount of NAND is limited, the onboard controller has to decide which chunks of data have the luxury of being accelerated. This certainly does boost performance but only in a finite number of applications and consumers have no say in what the controller thinks is important.
So how does Western Digital address these perceived shortcomings? Like the typical Hybrid, the Black² melds a relatively large hard drive and a ‘small’ solid state drive into a single device but its SSD portion has a 120GB capacity and its own controller. This means it is seen as a separate drive by the operating system and can be accessed directly by consumers, applications and the OS.
The easiest way to think of this new device is to consider it two separate storage drives that just happen to co-exist in one 9.5mm, 2.5” form factor and share on SATA port. In some ways it is almost a quasi Intel’s SSD Caching technology, though without the requirement for a supporting platform and with the OS installed onto the SSD portion.
By designing the Western Digital Black² 1TB, Western Digital have given consumers the power to control exactly what is stored on the fast – but still limited – NAND and what is not as time sensitive and can be stored on the single 1TB platter hard drive. As an added benefit the Black not only has the potential to be faster at read performance than the typical SSHD but will also be able to boost write performance. That’s something other hybrid solutions have historically struggled to accomplish.
By opening the case and looking inside we can see how Western Digital has been able to create this unique device. Like the name suggests, it is literally is two separate drives which only share the power and data ports. Everything else is separate which should potentially boost performance by a significant amount.
As an added benefit the Black² has more data retention fail-safes built in. Unlike the typical HDD+SSD combination which can only guarantee data retention in the case of NAND failure, if either the hard drive or solid state portion dies the data on the other half is completely secure and accessible.
The entire ‘top’ of the Black² consists of the SSD chassis which has been bolted down via three screws to the HDD’s internal caddy and uses integrated data connectors for point to point internal communications.
Taking a closer look we can see that this SSD is similar in its architectural design to that of some entry level SSDs such as the Corsair Accelerator. Instead of a full-size PCB it makes use of a much smaller PCB usually reserved for 1.8” or smaller form factor devices. It houses the controller, two 64GB 20nm MLC NAND ICs and a single NANYA branded DDR3-1600 128MB RAM IC for cache.
For the controller Western Digital has opted for the recently released JMicron JMF667HM8 which utilizes a four channel design and is TRIM capable.
The Black²’s bottom half consists of a separate 7mm form factor 1TB hard drive. In fact we have seen this drive before as it is a slightly modified Western Digital 1TB 7mm Blue Slim….that actually has the SLIM label still on it. By removing its we can see an additional Marvell 88SM9642 IC which is a SATA 3 port multiplier that allows both devices to 'share' the one SATA port. There is also an extra internal data connector which allows this PCB to communicate with the SSD.
When we previously looked at this 1TB, single platter drive we were less than impressed since a meager 5400RPM rotational speed relegated it to a small segment of the UltraBook marketplace. On the positive side, it does provide decent performance while still being extremely power efficient. Considering any time sensitive data can fit on the 120GB of NAND, this combination of ‘slow’ hard drive and ‘fast’ solid state is a much more sensible solution than others we have seen. These two drives are also picked up as two separate volumes which can be further partitioned.
While it may be sensible in our books, this combination does bring its own set of issues which may turn off some buyers. First and foremost is the price. A Seagate Laptop SSHD 1TB can be found online for an average of $120, whereas the Western Digital Black² 1TB has an MSRP of $299. This places it firmly in mid-tier 240GB SSD territory and it is treading dangerously close to what some 480GB SSDs like the excellent Crucial M500 can be found for. Desktop users can also look at Seagate's newest Desktop SSHD 2TB.
Some of the Black²’s relatively high price can be explained by its inclusion into a fancy “upgrade kit”, but a USB to SATA adapter cable, Acronis True Image data migration software and an extravagant book style box is not enough to entirely justify its premium. With that being said, with the level of performance Western Digital hopes to bring to the table, a $299 price for relatively high throughput may not be all that bad and those tools are welcome additions.
Unlike other hybrid drives, the new Black² cannot be placed in a RAID array and requires special drivers before the hard drive portion can be seen or accessed. At this time this means it is only Windows compatible and is certainly not ‘plug and play’. However the increased performance, ability to choose what is stored where and even the excellent 5 year warranty are all high points which may go a long way towards convincing buyers of Western Digital’s direction.
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