Seagate Momentus XT 500GB Hybrid HDD Review Wendy Robertson .

Is a “Hybrid” HDD the future?
Seagate think it is.
We review the Seagate Momentus XT 500GB hybrid HDD.
Can its performance compete with an SSD.
Let’s find out in this review.

Is a “Hybrid” HDD the future?
Seagate think it is.
We review the Seagate Momentus XT 500GB hybrid HDD.
Can its performance compete with an SSD.
Let’s find out in this review.

Seagate Momentus XT 500GB Hybrid HDD Review

Posted 04 November 2010 16:24 CET by Wendy Robertson



Review: Seagate Momentus XT 500GB (hybrid) Reviewed by: Wendy Collins Robertson Provided by: Seagate Model: ST95005620AS

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.

Drive bottom

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 1.1W.


Now let’s head to the next page where we will look at our test PC and testing procedures…