SLC, MLC or TLC NAND for Solid State Drives ?

SSDs (Solid State Drives) use NAND flash chips. Each of these chips contain millions of cells with limited number of write cycles. There are different types of NAND flash chips in use today with different characteristics as follows:


SLC (Single Level Cell) - highest performance, at a very high cost, enterprise grade NAND
~ 90-100,000 program/erase cycles per cell (highest endurance)
- lowest density (1 bit per cell, lower is better for endurance)
- lower power consumption
- faster write speeds
- much higher cost (3 times higher than MLC)
- good fit for industrial grade devices, embedded systems, critical applications.

eMLC (Enterprise Multi Level Cell) - good performance, aimed at enterprise use
~ 20-30,000 program/erase cycles per cell
- higher density (2 bits per cell)
- lower endurance limit than SLC, higher than MLC
- lower cost
- good fit for light enterprise use and high-end consumer products with more disk writes than MLC.

MLC (Multi Level Cell) - average performance, consumer grade NAND
~ 10,000 program/erase cycles per cell
- higher density (2 or more bits per cell)
- lower endurance limit than SLC
- lower cost (3 times lower than SLC)
- good fit for consumer products. Not suggested for critical applications which require frequent updates of data

TLC (Three Level Cell) - lower performance, lowest cost NAND
~ 3-5,000 program/erase cycles per cell
- highest density (3 bits per cell)
- lower endurance limit than MLC and SLC
- best price point (30% lower than MLC)
- somewhat slower read and write speed than MLC
- good fit for lower-end consumer products. Not recommended for critical applications which require frequent updating of data

Generally, SLC drives are the fastest, most relieble and most expensive drives available, usually used in the enterprise because of their consiredably higher cost. Both MLC and TLC are widely used consumer grade memory, with MLC being better in terms of endurance.

Notes: Larger TLC drives may yield similar longevity as smaller MLC drives, considering you can average out the wear over higher number of cells.