#SSD Flash drives: #SLC or #eMLC or #MLC or #TLC NAND… but also V-NAND

Flash drives or Solid State Drives (SSD) use NAND flash memory chips, on each chip millions of cells with a limited life span (limited write operations). NAND comes in differente grades of performance, cost & reliability.


SLC (Single Level Cell)  ****
– HIGHEST performance, High Cost, Enterprise grade NAND
– HIGH cost (3x more than MLC)
– industry grade, critical apps
– endurance: 100.000 write/erase operations per cell

eMLC (Enterprise Multi Level Cell) ***
– GOOD performance, enterprise use
– LOWER cost
– 2 bits per cell
– enterprise use and high-end consumer
– endurance: 30.000 write/erase operations per cell

MLC (Multi Level Cell) **
– AVERAGE performance, consumer grade NAND
– LOWER cost (3x lower than SLC)
– 2 or more bits per cell
– consumer, not suggested for critical apps with frequent updates of data
– endurance: 10.000 write/erase operations per cell

TLC (Three Level Cell or 3-bit MLC) *
– LOWER performance,
– 3 bits per cell
– BEST PRICE (30% of an MLC)
– good fit for low-end consumer
– not recommended for critical applications with frequent data updates
– endurance: 5.000 write/erase operations per cell

On the opposite of the previous described planar NAND, also consider the new Vertical NAND (V-NAND) technology, 2-bit & 3-bit which increased capacity needs by stacking cells in multiple layers in stead of shrinking the cell geometry thereby avoiding performance & endurance issues of cell-to-cell interference.
Performance of a 3-bit V-NAND is higher the 3-bit NAND

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