Western Digital Black2 Dual Drive Review (1TB HDD/120GB SSD) – Combining SSD Performance with HDD Capacity


This first set of benchmarks represents testing of the WD Blue Slim 1TB 5400 RPM HDD by itself.  It is designated as drive letter D: in the applicable screenshots.


Crystal Disk Info gives us quite a bit of excellent information about our HDD, including serial number, firmware version, ‘power on’ information and overall drive health status shown as “good”.  On the WD Black2, CDI is looking at the “disk” instead of the “partition”. With the HDD and SSD sharing a single SATA connection, CDI sees the combined disk of 1120.2 GB even though we are only accessing the HDD for testing purposes.

WD Black2 HDD only CrystalDiskInfo


ATTO Disk Benchmark has been around as long or longer than most any other storage performance benchmark.  ATTO uses RAW (or compressible) data, and for today’s benchmarking test we will use a set length of 256MB.  We will be testing both the read and write performance of various transfer sizes ranging from 0.5KB to 8192KB.  This is the testing method preferred by most manufacturers, as it tests with RAW (compressible) data, rather than random (including incompressible) data.  Although random and incompressible data may be a more realistic usage scenario, testing with it will give lower performance results.

WD Black2 HDD only ATTO

Beginning with a transfer size of 16KB, and all transfer sizes larger, the WD Black2’s HDD portion plateaus at around 114-115 MB/s reads and 112-114 MB/s writes.


Crystal Disk Benchmark is used to test read and write performance through sampling of raw (0/1 fill / compressible) data, or random data that is mostly incompressible.  The left screenshot displays the compressible (zero fill) results, and the right screenshot displays incompressible (random data) results.

WD Black2 HDD only CrystalDiskMark zero fillWD Black2 HDD only CrystalDiskMark random

As you can see, the HDD’s performance in CDM is unaffected by what type data is being read or written.  Sequential and random benchmarks both are surprisingly equal in all testing categories.

Although the next two benchmarks are pretty much SSD-specific, we will include them for a comparison basis.  They also further demonstrate the dramatic difference in transfer speeds between HDDs and SSDs.


AS SSD was until recently the only benchmark created specifically for SSD testing, and it uses incompressible data.  For the most part, AS SSD shows us “worst case scenario” SSD transfer speeds because of its use of incompressible data.  Enthusiasts often prefer AS SSD for this reason, as they seek to see minimum performance as well as maximum performance.  Transfer speeds in MB/s are shown in the left screenshot, IOPs in the right screenshot.

Wd Black2 HDD only AS SSD MBsWD Black2 HDD only AS SSD IOPS


WD Black2 HDD only AS SSD copy benchmark

AS SSD’s worst case scenario being represented here is a vivid reminder of what it would be like to have to revert to this type of performance after having utilized SSDs for any length of time.  The AS SSD copy benchmark times are definitely HDD-slow.


Anvil Storage Utilities is an absolutely amazing SSD benchmarking utility.  Not only does it have a pre-set SSD benchmark, but also includes such things as endurance testing and threaded I/O read/write/mixed tests, all of which are very simple to understand and utilize for benchmark testing.

WD Black2 HDD only Anvil Storage Utilities

And yet again with Anvil, we see the dramatic difference between HDD and SSD performance.


  1. I’m no much of a laptop person and i think it wont do me any good since i use mine for work(not on desk) and its constantly moving, and hdds parts are kind a risky, so 100% SSDs for laptops or any mobile device. But i wike to see bigger HDD for work at home ! Very helpful review !

  2. the NAND is known to be 20nm but you don’t know the vendor? how is that? technically Sandisk and Tosh do not have 20nm process.

  3. I bought one of these and have installed it with programs on SSD and data on the 1TB HDD.
    I find the 1TB HDD slow to respond to document opening etc. I would have preferred a 7,200 rpm HDD connected to the SSD

  4. Love this product… Installed it 6 months ago and it made my 3 year old laptop respond faster than my friends 2015 gaming laptops (with sshd in it). Money well spent.

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