Just recently, laptop users were faced with a problem where they could either install a large capacity hard disk or a limited capacity SSD based on what they could afford. Seagate aims to overcome this issue with the launch of its Momentus XT line of hybrid hard disks, which are a combination of a solid state disk and hard disk in the same package, but at a price not much higher than an equivalent capacity 2.5″ hard disk. Now AnandTech has carried out a review of it to see how it stands up against a few popular SSDs and traditional hard disks.
The Seagate Momentus XT features 4GB of SLC NAND on-board. While this does not seem like much storage, the drive actually uses the NAND purely as a read cache. By monitoring what sectors or small blocks of data are read 2 or more times, the drive places this data in the NAND, so that future reads will be read from the NAND instead of the platters. Larger and less frequently used blocks of data are left on the platters.
As an additional boost, the drive spins at 7200RPM and has a 32MB buffer, the largest cache Seagate has yet on a 2.5″ Momentus drive. To save power, the drive spins down after a period of inactivity and if the read requests are cached in the NAND, this data is read without spinning up the platters. The drives are available in capacities of 250GB, 320GB and 500GB.
So how does the drive perform in real-world testing? AnandTech finds out in its series of tests, which include Windows booting, application launches and opening files. These are repeated several times to show the NAND taking effect. The review finally looks at several synthetic tests and AnandTech’s own Storage Bench tests. Read the full review on AnandTech.