SSD datasheets are written in a vocabulary of their own: TLC, QLC, 3D NAND, DRAM cache, TBW, over-provisioning. Understanding a handful of these terms is enough to choose the right drive and avoid the wrong one. This article explains them and then applies them to KingSpec’s range.
What NAND flash is
NAND flash is the memory that stores data in an SSD. It is non-volatile – it keeps data without power – and it is organised in cells, pages and blocks. Data is written in pages and erased in blocks, and each block can only be erased a finite number of times before it wears out. Everything about SSD design follows from those two facts.
Cells: SLC, MLC, TLC, QLC
A cell stores one or more bits depending on how many voltage levels the controller can distinguish. SLC stores one bit per cell: fastest, most durable, most expensive. MLC stores two, TLC three, QLC four. Each step increases capacity per chip and reduces cost, and reduces endurance and sustained write speed. Almost all consumer and mainstream enterprise drives today are TLC; QLC is used for high-capacity, read-heavy storage; SLC and MLC survive in industrial drives where endurance matters more than cost.
3D NAND
Early NAND was planar: cells laid out flat, shrinking each generation until they became unreliable. 3D NAND stacks cells vertically in dozens to hundreds of layers, which increases density without shrinking the cell. It is why a 2 TB drive costs what a 256 GB drive cost a decade ago, and why modern TLC endurance is adequate for most workloads.
The controller and the cache
The controller is the processor in the SSD. It maps logical addresses to physical pages, spreads writes across blocks so that no block wears out early (wear levelling), moves data around to free blocks (garbage collection), corrects errors and manages the cache. A drive with a DRAM cache holds its mapping table in fast memory and performs consistently under mixed workloads; DRAM-less drives use a portion of the host’s memory or an SLC cache on the NAND and are cheaper, with a performance drop under heavy sustained writes. For office PCs the difference is rarely noticed; for servers it is.
Endurance: TBW and DWPD
TBW (terabytes written) is the total the drive is warranted to write. DWPD (drive writes per day) expresses the same thing per day over the warranty period. An office PC writes perhaps 10 to 20 GB a day; a 600 TBW drive would last decades. A video recorder writing 2 TB a day would exhaust the same drive in under a year, which is why surveillance and database systems need drives rated in DWPD.
Over-provisioning and power-loss protection
Over-provisioning is spare NAND the controller keeps in reserve for wear levelling and garbage collection; enterprise drives reserve more, which is why a drive marketed as 960 GB and one marketed as 1 TB may use the same NAND. Power-loss protection is capacitors that let the controller finish writing cached data if power fails, and it is the feature that separates drives safe for databases and industrial controllers from drives that are not.
Applying this to KingSpec
KingSpec’s consumer SATA and NVMe drives use 3D TLC NAND and are the right choice for office fleets and laptops. Its industrial line steps up the NAND grade and adds power-loss protection and wide-temperature operation for embedded and unattended systems. Its enterprise SATA drives are specified in DWPD for servers and recorders. The datasheets state NAND type, TBW, cache configuration and temperature range, which is what to compare.
Choosing well
Match TBW or DWPD to the workload, choose DRAM-cached drives for servers, insist on power-loss protection where power is unreliable, and pick the interface the system actually has. Then standardise so that support is simple.
KingSpec through Zen
Zen Interactive Technologies distributes KingSpec in the UAE and GCC and can help translate a workload into a drive specification. See the KingSpec page for the range and datasheets.