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 … Read more