Standard laptop hard drives (2.5-inch) come in three tiers based on their thickness: 9mm, 12.5mm, and 7mm.
The first one, such as the Seagate Momentus XT (500GB), is the most popular and used in most notebooks and other 2.5-inch-based storage applications. The 12.5mm standard, such as the 1TB WD Corpio Blue, is a newer standard that offers higher capacities but can only fit in later models of laptop computers. The third, 7mm tier is used for ultraportable applications, such as Netbooks or tablet PCs. For a long time, this ultracompact tier of internal hard drive was known to be slow and come with limited storage capacities.
Hitachi unveiled Tuesday its latest in ultraslim hard drives, the Z-series of TravelStar and CinemaStar. The TravelStar is for ultraportable computing devices, whereas the CinemaStar is for audio and video (AV) streaming.
The company claims that both of them offer low power consumption, shock resistance, quiet acoustics, and up to 320GB of storage, which is currently the highest among 7mm 2.5-inch hard drives.
The new Hitachi Z-Series family includes three hard drives:
The Travelstar Z7K320 hard drive: This is the first 7mm 2.5-inch hard drive in the industry that spins 7,200rpm. The drive also has 16MB of cache memory and supports the Serial ATA 3Gbps. Hitachi claims that the drive can deliver up to an 18 percent improvement in application performance over the 5,400rpm models of the same capacity. The drive features a halogen-free design and low power consumption at just 1.8 watts during operation and 0.8 watt when idle.
The Travelstar Z5K320 hard drive: This is the lower-end ultraportable SATA 3Gbps hard drive that has 8MB of cache and spins at 5,400rpm. The drive consumes even less energy than the Z7k320 with just 1.6 watts during operation and 0.55 watts when idle.
The CinemaStar Z5K320 hard drive: Hitachi claims that this is the first 7mm hard drive designed specifically for AV-streaming devices, such as set-top boxes and DVRs. It allows these device to stay compact while offering a large amount of storage. The drive comes with 8MB of cache memory, supports SATA 3Gbps, and spins at 5,400rpm. It also futures low-energy consumption and quiet acoustics.
Despite the ultrathin design, the new Z-series hard drives share the same port configuration with other 9mm SATA hard drives and therefore can be used in any application where other 2.5-inch SATA hard drives are used.
Hitachi says the new drives are currently shipping in volumes to OEM manufacturers, so it's unclear how much they cost individually. However, according to Hitachi, they offers the most cost-effective storage solution in terms of cost per gigabyte, especially when compared with that of solid-state drives.