Reviews, VR World

WD Nearly Perfectly Combines SSD and HDD into The WD Black2

When you look at the introduction of SSDs into the laptop market one of the biggest problems was the lack of capacity. Even to this day, capacity is an issue for most solid state drives simply because high-density NAND isn’t very fast and generally doesn’t come very cheaply if it is fairly fast. As a result, you get SSDs that are in the sub 500 GB capacity range for over $300. The state of affairs a year or two ago was much much worse and things have only recently gotten better, but even so less than 500 GB of storage isn’t much for most people.

As such, most users end up using an SSD for their OS and applications and a hard drive for their media and other data. This way, one could purchase a very fast SSD in a lower capacity and a large hard drive for storing all of their documents, music and movies. In a laptop this is problematic because you are generally fighting for space in an already cramped environment. As a result, most laptops will either offer you an SSD or a hard drive, unless they are big enough to have two 2.5″ drive bays. Western Digital made the WD Black2 because of the desire from the community asking for a drive where such a decision didn’t have to be made. The WD Black2 is designed to remove that choice from the mobile user’s build decisions and to give them both of what they want in a single drive solution.

The WD Black2 is a 2.5″ laptop-sized drive that is less than 10mm thick (9.5mm) and houses both a full 120 GB SSD and a full 1 TB hard disk drive. As a result, users and OEMs no longer have to decide whether they want to sacrifice capacity for speed or speed for capacity. With WD’s Black2, users can have the best of both words in a ridiculously tiny package. This drive is not to be confused with some other solutions out there, including some of WD’s own SSHD solutions that combine NAND flash for caching with a hard drive for added speed. This is not an SSHD, this is an SSD and an HDD in a single drive with two completely independent drives, except for one part. The SSD and the HDD on this drive share the same SATA 6Gb/s connector for both data and cable. This could prove problematic if there is a lot of traffic going to and from both drives and could be a possible bottleneck of the drive.

In our review, we will be evaluating the WD Black2’s ability to operate as an SSD and as an HDD and in another article, we will talk about the upgrade process of a laptop that runs a traditional hard drive. We will also be evaluating Western Digital’s performance claims of 350 MB/s sequential read and 140 MB/s sequential write speeds.

In terms of the drive’s specs, we’re pretty light on details but we do know that it is a 120 GB SSD and a 1 TB HDD and that the overall thickness is 9.5mm. We also know that this is a 5400 Rpm hard drive with 16 MB of cache and that the SSD is using 20nm NAND and Nanya DRAM (found that out for ourselves). We asked WD what controller they were using for the SSD, but we weren’t given an answer and may have to tear the damn thing apart ourselves. We also took some pictures of the PCB of the drive and noticed that in WD’s official product photos they erased all of the markings of the WINBOND memory chip and some WD Redfish controller that we couldn’t find anything about but assume it is HDD and not SSD related.

First Experience and Impressions

First, we needed to unbox the drive, which was presented in a very fancy manner for a hard drive, considering all of the nice packaging. The contents of the box were simply the drive itself, a USB drive cut out of paper made to look like a key and a USB 3.0 dongle to connect the drive to an existing computer for an easy upgrade. Even though, WD said that they generally recommend this drive to be used in new builds in order to prevent any possible data loss. I wanted to test the usability of the dongle on the front of my Lian Li case and it actually was too short between the USB 2.0 (for power) and 3.0 ports (data). If you want to plug this thing into your case and image over your data, you better connect it to the back of your computer where all the USB ports are much closer. Although realistically, this would be used for a laptop upgrade and would only need two ports to be next to each other.

Upon opening the drive, I hooked it up to my PC via a SATA 6Gb/s on my X79 test bench and powered it on. Upon doing so, I tried using the key that WD had provided me with the drive to download the software needed for the rest of the drive to be recognized by the computer. When you plug the drive into your computer for the very first time, the computer only sees the 120 GB SSD and until you install the WD software, the 1 TB drive will not be visible. Unfortunately for us, this website would not go live until this product is public, which will be after this review.

For those of you looking to use this drive, that USB key will direct you toward the file download that you need to get this drive fully enabled. Once the software is installed, you then need to make sure that the drive you are using is fully initialized by the computer (does not have to be formatted yet). If you have installed an operating system to the 120 GB SSD, this is not an issue. However it may be an issue if you are testing it as a secondary or tertiary drive like I am.

Once the drive has been initialized, you can then check the web for updates to the drive, in our case there weren’t any. And then once you’ve installed the drivers for the drive, the 1 TB drive simply pops up and all of the setup is already done for you. Do keep in mind that this software is currently only supported on Windows and there is no support for Mac, yet. The software also does not support RAID nor any Nvidia or ASMedia storage controllers. Once you’ve formatted both drives, you will get just a hair over 1 TB of total drive space as opposed to 1.12 TB unformatted.


After both drives were properly installed and formatted, we got to testing our drive. The first test we did was a purely theoretical synthetic benchmark that many of you know. In the ATTO test we were merely seeing how close the drive got to its theoretical maximum speed and what could be possible in the best case scenarios.

Here, we tested both the SSD and HDD (respectively) separately in order to obtain the fastest possible speeds from each. From our testing, we can see that the SSD portion of the drive is capable of read speeds up to about 350 MB/s and about 100 MB/s write  while the hard drive portion of the drive did both a read and write speed of about 113 MB/s for any file size 64 KB or larger. This is clearly the closest that we can get to Western Digital’s performance claims of 350 MB/s read and 140 MB/s write.

Moving on from ATTO, we tested another synthetic benchmark called CrystalDiskMark which is generally MUCH closer to the drive’s real world performance than ATTO. If you ever want to do a quick test of a drive’s capabilities CrystalDiskMark is usually the fastest way to get a reliable result.

In CrystalDiskMark, we did a similar test where we tested just the SSD and HDD separately to give you an idea of how fast each of them was on their own. Here we see that the SSD’s sequential read speeds are up to 340 MB/s and write speeds are up to 102 MB/s. With the hard drive, we can see that sequential speeds for both reads and writes were 117 MB/s. In terms of smaller file sizes, the SSD absolutely wiped the floor with the HDD in 4K file sizes coming in over 20 times faster, which means that you know where files of smaller sizes should belong in this drive configurations. Random 512K performance on the SSD was also quite good, with read speeds being about 5 times faster than the hard drive.

Next, we tested the SSD portion of the drive in the Anvil Pro SSD benchmark. This benchmark does a sequence of different file sizes and measures the drive’s IOPs as well as speed.

As you can tell here, the drive performs much closer to 300 MB/s in sequential 4MB file size reads and 88 MB/s in 4MB sequential writes. Both of these figures are a solid 20-30 MB lower than what we saw in ATTO and CrystalDiskMark.

After we thoroughly evaluated the synthetic benchmark performance of each component of this drive, we wanted to test what would happen to the drive’s performance if both drives were being tested simultaneously. I thought that this would be necessary to test because both drives share the same SATA interface and I wanted to know if the SATA interface gets clogged when both drives are doing heavy IO.

For this test, I ran CrystalDiskMark on the 1 TB hard disk portion of the drive while Anvil Pro ran on the solid state portion of the drive. If you compare these performance numbers to the results from above, you can see that the hard drive doesn’t take much of a penalty while the SSD takes a pretty big penalty to the read speeds compared to the earlier Anvil test above. This was a little disappointing to see that there was in fact a performance hit when both drives are being heavily loaded. But realistically, the most any user will see is the occasional download coming down at 10-15 Mbps and some file reads here and there from the SSD. Nothing like what you would see from our strenuous testing.

After I did that, I wanted to see how the drives would behave in real world scenarios. We did this by testing a series of different types of media files, photos, videos, and audio that were a total of 11.2 GB in size. By moving these files between the drives already in our system and this drive we wanted to see how fast our transfer rates really were in the real world using real world files. The test that interested us the most were real world writes since the write speeds were so close on each drive.

Hard Drive Test

SSD Test

In our real world write tests, we actually saw that the hard drive was faster to write to from any medium (USB, SSD or HDD). As such, it seems logical that most applications will take a little more time to install to the SSD than they will to the HDD, however, you will get a lot faster application performance from the SSD once those files are written to the SSD. The good write times on the HDD are also a good thing for people that download a lot of games, movies and music since they can easily point all downloads to the hard drive without worrying about the SSD being the slower of the two or running out of space.

The most concerning part about this drive, though, was when we sent data between the SSD and the HDD. In each instance, we got speeds of 39 MB/s and 53 MB/s which is about half of what we saw on the write speeds of each of these drives in all of the various tests that we ran.



I suspect this is because in order for the data to go from the SSD to the HDD and vice versa, it must travel out to the SATA controller and then back to the drive again and it will most likely still be sending outward bound data while it is also receiving it. Because the drive does not have any cache that connects the two drives together, there is nowhere to pool these kinds of intra-drive data transfers. Even though the two drives are on the same physical drive, it isn’t just like moving a file around on a hard drive or an SSD, these two drives act almost entirely independently except for the SATA interface that they share.


In terms of value, this drive is certainly an interesting proposition. First and foremost, this drive will be selling for $299.99 or a cool $300 for the people that like to keep it simple. At $300, this drive certainly comes off as an expensive SSD or a ridiculously expensive 1 TB HDD. Right now, on Newegg, a 1 TB hard drive with similar specifications sells for $100 and an SSD with similar specifications sells for $100 as well. To be fair, though, the SSD will probably be faster than the SSD that we have on the WD Black2, but it is also much bigger.

So, for $200 you could have about the same amount of capacity and two drives. In the case of this drive, by combining the two drives together, Western Digital believes that the WD Black2 is worth an extra $100 over a two drive solution. Clearly, this solution isn’t intended for desktop users that could easily just buy two drives and save money. This is clearly a solution for people that have no choice and have to pick between one drive. And now, for the price of $300 they no longer have to pick at all. Do keep in mind though that for about $300 there are some 480 GB SSDs available which is about half the capacity of this drive but a fair bit faster. But once again, a sacrifice between capacity or speed needs to be made.

Also, in addition to being a solid state and a hard drive, this drive also carries a very non-standard 5 year warranty. Which is pretty much unheard of in the world of consumer SSDs or consumer laptop hard drives. This means that either Western Digital is going to be replacing a lot of WD Black2’s in the next 2-3 years or they really have designed these things to last even though they are a brand new type of drive with all different types of new technology.


The idea of allowing people to have both an SSD and an HDD in the same form factor and size as a standard laptop hard drive is a brilliant one. I have no doubt that a lot of people are going to want to get one of these drives simply because they enable vast amounts of storage and a fairly fast SSD. The amount of innovation necessary to accomplish this is pretty astounding on both the HDD and SSD technology levels and the combination of the two.

While many users may choose to go with a 1 TB drive for the capacity and relative cheapness and other users may go for a 480 GB SSD for over $300, I believe that this drive is a solution that allows people a choice that they simply didn’t have before. It clearly isn’t perfect yet and we’ve already indicated to WD that we would like to see larger SSD capacities, but right now this is what they can do as a first product until they can get more traction and demand from consumers for more. The drive’s performance didn’t necessarily blow us away, but the innovative thinking and sheer difficulty of pulling something like this off is an amazing task in of itself.

As such, we are awarding the WD Black2 our Enthusiast Innovation award because at the current price point I don’t quite consider it mainstream just yet. Especially when you consider that it is a one of a kind drive and most of the first adopters of this drive will probably be enthusiasts looking to upgrade their laptops to SSDs and bigger HDDs.