Specifications
Flash Memory Guide
6
5.1 Die-Stacking
Many semiconductor manufacturers use a“die-stacking”technique to increase a Flash memory chip’s capacity. After
the semiconductor wafer fabrication process, they cut out the Flash memory silicon “die” and then attach or stack
multiple dies together.
For example, when a semiconductor manufacturer stacks two 32 gigabit dies together, they form a single 64 gigabit
Flash memory chip.
Die-stacking allows for cost-reduction alternatives to the larger-capacity chip, single-die chip (called “monolithic”
chips). Stacking two 32-gigabit chips together, for example, typically costs far less than buying a low-volume
monolithic 64-gigabit chip. The 64-gigabit chip can then be used to build a 8GB Flash card (single chip card), or a 16
GB Flash card (two chips on one card).
Die-stacking is similar to the DRAM chip-stacking technology that Kingston utilizes to produce high-end server
modules. As a result, Kingston’s die-stacked Flash cards are reliable and deliver high performance.
5.2 Multi-Level Cell (MLC)/ Triple-Level Cell (TLC) Flash Technologies
NAND and NOR Flash memory chips store one (1) bit value (a “0” or a “1”) in each cell. In multi-level Flash technology,
two (2) values are stored into each cell. In triple-level Flash technology, three (3) values are stored into each cell.
Kingston has incorporated both MLC/TLC Flash memory into its line of standard Flash cards, SSDs and DataTraveler
USB Flash drives.
6.0 Flash Storage Device Performance
Flash card storage device performance depends on the following three factors:
• The specic Flash memory chips used: Generally, there is a tradeo between the high-speed and more expensive
Single-Level Cell (SLC) Flash chips, and the standard speed and more aordable Multi-Level Cell (MLC)/Triple-
Level Cell (TLC) Flash chips.
• The Flash storage device’s controller: Today’s Flash storage devices have a built-in Flash memory controller. This
special chip manages the interface to the host device, and handles all the reads from and writes to the Flash chips
on the Flash storage device. If the host controller is capable of supporting faster data transfer speeds, the use
of optimised Flash controllers can result in signicant time savings when reading or writing data into the Flash
memory.
• The host device to which the Flash storage device is connected to: If the host device (computer, digital camera,
cell phones, etc.) is limited to specic read and write speeds, using faster Flash storage devices will not deliver
higher performance. For example, using a USB 3.0 Flash drive on a computer that supports only USB 2.0 speeds
will not result in faster transfers. In addition, computers need to be properly congured to support faster transfers
in both hardware and software. In the case of a PC, the system board will need to have built-in SuperSpeed
USB 3.0 connectors, and the Operating System (e.g., Windows) will also need to have the proper USB 3.0 drivers
installed in order to be able to support SuperSpeed USB transfers.
For details on USB Performance, refer to Appendix A.
Flash memory product manufacturers provide “x-speed” ratings for Flash cards. However, due to a lack of industry
standards, comparing dierent Flash products may prove dicult for consumers. For details, see kingston.com/
Flash/x-speed.
Kingston works closely with global semiconductor and controller manufacturers to ensure that Kingston Flash
devices deliver superior price/performance to its customers. For enthusiasts and advanced customers demanding