Seagate Momentus XT Review

The Seagate Momentus XT combines traditional spinning storage technology with non volatile silicon-based flash memory in an attempt to get the best of both worlds, ultra fast access and massive capacity at an affordable price.

Just as some current processors come with three levels of cache for optimal performance, the Momentus XT drive has three different storage packed in one; there's a 32MB buffer, then 4GB onboard SLC flash (not MLC) and finally 500GB capacity on the model we tested.

Note that Seagate doesn't quote their hard disk drives as sporting the additional 4GB storage but instead labels it as "Adaptive Memory", one which automatically adjusts its performance to suit the users' needs by monitoring "your frequently used applications and data files, then placing them into the solid-state portion of the drive so that they can be recalled quickly".

In a nutshell, it looks a lot like what Windows' Readyboost does but is OS, driver and software independent (ed : it would be interesting to find out what would happen if the Momentus XT was combined with Readyboost).

It also means that improved performance can only be obtained over time rather than straight out of the box as the algorithm "learns" the user's habits; which is the opposite of what you'd expect from SSD technology.

It has a SATA 3Gbps interface with NCQ, something you have to bear in mind should you want to upgrade your existing storage solution. The model we tested, ST95005620AS, has an areal density of 394Gb per square inch which is significantly less than the 541Gb per square inch that the biggest Momentus member (a 750GB model) sports; in other words, there's room for the XT's capacity to grow.