According to Kingston Technology Support
Kingston has some of the drive allocated to a hidden area. Most likely a certain chip with cells. Not accessible by the user. A hardware hack would allow you to possibly see what is truly being held there.
The Hidden area could hold. Reserve cells for longer life of the drive and the firmware as controller information.
A reference the website is below.
Some of the flash storage device's listed capacity is used for formatting and other functions and thus is not available for data storage, therefore you will not see the full capacity.
When a flash storage device is manufactured, steps are taken to ensure that the device operates reliably and permits the host device (computer, digital camera, PDA, etc.) to access the memory cells; i.e., to store and retrieve data on the flash storage device. These steps, loosely called "formatting," utilize some of the memory cells within the device and thus reduce the capacity available for data storage by the end-user.
Formatting includes the following operations:
Testing each memory cell in the flash storage device.Identifying all defective cells and taking steps to ensure that no data will be written to or read from a defective cell.Reserving some cells to serve as "spares." Flash memory cells have a long but finite lifetime. Therefore, some cells are held in reserve to replace any memory cells that may fail over time.Creating a File Allocation Table (FAT) or other directory. To enable flash storage devices to conveniently store and access customer files, a file management system must be created to allow any device or computer to identify the files stored in the flash storage device. The most common type of file management system for flash storage devices is the File Allocation Table (FAT), which is also used on hard drives.Reserving some cells for use by the flash storage device's controller, e.g., for storing firmware updates and other controller-specific information.Where applicable, reserving some cells for special features. For example, the specification for Secure Digital (SD) cards requires reserved areas to support special copy protection and security features.
FAQ: KDT-010611-GEN-06