We've known for a long time that the blending of traditional platter drives with the inherent speed of SSD's was inevitable. Leave it to Seagate to field the first production Hybrid Platter/SSD in the Seagate Momentus XT. The drive we have in hand comes in capacities of 500, 320 and 250 GB and the one we have in house happens to be the 500 GB Model.The Momentus XT has a standard Sata 3GB/s interface, a normal cache of 32MB and a 4GB SSD that is used as an intelligent cache that learns what you use and optimizes the payload of the 4GB SSD according to your specific needs. The Momentus XT does that on an ongoing basis, if your habits change the drives SSD Payload changes with you.Normal benchmarks and tests aren't going to do this drive justice. Benchmarks like ATTO, HDTach, and Sandra are simply synthetic benches and the drive has no chance to learn. So programs like PCMark Vantage and Sysmark have to be employed to show the drives learning capabilities. The adaptive memory technology on the Momentus XT takes what you use on a daily basis and moves it to the SSD portion of the drive so it's ready for you in a flash (A Nand Flash of course). Since the Data exist both on the SSD portion and the Platter portion if something should happen, or the Nand Flash fails your data is still intact. That takes a lot of the worries away from end users who believe Nand Flash is a more fragile storage medium. Having had 14 SSD's in hand an having none fail we tend to think that the perception that Nand Flash as being fragile is mostly myth (Or bad luck on the part of a few end users).Having experienced the Seagate Momentus XT from Beta testing to full production run we can honestly tell you Seagate has the right idea. Given the exorbitant cost of SSD's and their small storage space Hybrid drives make sense. A lot of the performance gains of an SSD when you need them, and the larger storage capacity (and smaller price) of platter drives.