Seagate was kind enough to send us one of their latest HDD’s
for review; the Momentus XT 500GB. The Momentus XT series of drives have a 2.5
inch form factor, SATA2 connection and SATA power connector. The Momentus XT is
however different from other HDDs, as the Momentus XT is a “hybrid” drive. The
Momentus XT has traditional spinning platters for storing data, but also 4GB of
SLC (single level cell) NAND for caching frequently used files, which can be OS
files or frequently used applications.
The Seagate Momentus XT series can be fitted to a laptop
with SATA hard drive support, or as we have done for most of the tests in this
review, the Momentus XT series can also be fitted to a desktop PC which
supports SATA hard disk drives, by means of a 3.5 inch to 2.5 inch mounting
bracket (not supplied with our review sample).
The idea of a hybrid drive is you have SSD like speeds for
launching applications courtesy of the high speed NAND, which provides
lightning fast access times, but also large storage capacity at minimum cost
provided by the traditional spinning platters, and in the case of our review
sample, 500GB of storage.
So how does it work?
You have 4GB of SLC NAND configured as a read cache. When
you write data to the drive, the drive places this data on the spinning
platters and the NAND is not used at all for writing data.
The Momentus XT has a technology that Seagate calls “Adaptive
Memory technology”. Basically this involves analysing and learning the user’s
work pattern. Let’s look at an operating system, for example.
To boot an OS such as Windows 7 to the desktop, a large
amount of files have to be read from the HDD into system RAM every time you
boot the PC. Adaptive Memory Technology will analyse which files are loaded,
and then store some of these files in the NAND, and then create a table
somewhere on the drive which redirects reads to the NAND rather than from the
platters, and by doing so cuts down the access times dramatically. These files
are then left there until you defragment or format the drive.
Once you’re at the desktop and start launching applications,
the same applies. Adaptive Memory technology will analyse the files required to
launch an application, and then store the files in NAND, and finally update the
table to redirect reads from the platters to the NAND. Again this speeds up the
time to launch an application dramatically.
When you first launch a new application, speed is as from a
normal HDD, but launch the application a couple of more times and you will find
the application launches much faster. In essence, you get what is approaching
SSD speeds for system boot and application launches. Of course, the Momentus XT
only has 4GB of NAND, so every application and its files can’t all be stored in
NAND, but none the less, the boost in performance over a traditional spinning
HDD is quite remarkable, as we will see later on in this article.
Can a hybrid HDD provide SSD like performance?
Let’s find out in this review with our range of benchmarks and real world tests.
Seagate company information
I’m sure most MyCE members will be familiar with the Seagate
brand name. Seagate have been manufacturing HDDs for as long as I can remember.
If you would like to find out more about Seagate, you can
visit the Seagate website.
Our review sample was a bare drive, housed in a plain
cardboard box with adequate foam protection to prevent damage during transit
What’s inside the box
Now it’s time to take a look at the drive itself and what
the drive came shipped with.
The package contained the Seagate Momentus XT hybrid drive
itself, and we can see that the drive came shipped with firmware SD23. We can
also see the capacity of the drive printed on the label, and also that the
drive was manufactured in China.
Now let’s take a look at the underside of the drive.
On the bottom of the drive we can see a PCB and the spindle motor;
we did not feel comfortable in removing the PCB to take a look at the populated
side of the PCB. However, we can on the print side see what appear to be the
land zones for the 4GB of SLC NAND, and we can also see the drive’s SATA power
and data connectors.
From the above screenshot taken from HD-Tune Pro, we can see
that the drive platters have a rotational speed of 7200rpm, and supports
S.M.A.R.T., power management including APM, NCQ, read and write cache, and that
the drive supports SATA2. There is no TRIM support for the NAND, but TRIM is
not required for this drive in its present configuration.
From the above screenshot, we can see that the Momentus XT
has a spindle speed of 7200rpm for the platters, 32MB of cache, a SATA2
interface, consumes 0.8W at idle, and an average operating power requirement of
Now let’s head to the next page where we will look at our
test PC and testing procedures…