Early this morning, Seagate lifted the lid on the Momentus XT, a 2.5" hybrid notebook hard drive that combines capacious mechanical platters with speedy flash memory. On the mechanical front, the drive offers 250, 320, or 500GB of storage capacity on platters spinning at 7,200 RPM. Seagate pairs the mechanical storage with 4GB of SLC flash memory, using a scheme it has dubbed Adaptive Memory.
Unlike previous attempts at the hybrid drive concept, the Momentus doesn't rely on Windows to manage the contents of its flash module. Instead, the drive intelligently populates its flash memory based on user access patterns. As one might expect, frequently accessed data is a prime candidate for caching. Adaptive Memory can also favor data that may not be needed as often but is particularly slow to access due to its physical location on the drive platters.
The drive's flash memory isn't used to cache writes. However, the Momentus XT has an ample 32MB DRAM cache to help on that front.
The hybrid drive also comes with a 3Gbps Serial ATA interace and has a standard 9.5-mm height, which should ensure compatibility with most laptops. You can expect to pay $113, $132, and $156 for the 250, 320, and 500GB variants of the drive, respectively.
Obviously, we don't have a review for you this morning. Our apologies. We'll have one up just as soon as we can get our hands on an XT to test. However, we're not sure when that will be. Seagate contacted us a couple of weeks ago about doing a review of the Momentus XT, and we eagerly agreed. Unfortunately, the drive never showed. First, we were told it had shipped and would arrive on the 14th. Then, the following week, we were told the first shipment didn't go out, but our sample would arrive on the 20th. Fair enough. New hardware often gets delayed, and this isn't wouldn't be the first time I've had to clear a weekend for testing. But the 20th came and went, and so did the rest of the weekend. Still no drive.
In somewhat related news, today also marks the introduction of a 750GB, 7,200-RPM addition to Seagate's traditional Momentus family. This drive doesn't have any hybrid trickery, but with 375GB per platter, it has a much higher areal density than the Momentus XT, which only has 250GB per platter. Unfortunately, none of the Momentus XT reviews that I've seen around the web have tested the 750GB Momentus, which could be faster than the XT in some scenarios due to its higher bit density. A 750GB Momentus is supposedly coming with our XT sample, so we should be able to see how the two drives fare against each other. Eventually.