A little less than two years ago, Samsung surprised the storage industry by unveiling the world's first 3-bit MLC, or TLC (Triple Level Cell), NAND based SSD, the Samsung 840. At the time, TLC NAND had already been in use for storage applications such as flash drives and embedded systems, but nobody really thought TLC was viable for SSDs due to TLC's inherently higher latency and its lower endurance compared to older MLC and SLC technologies.

Despite this, Samsung is now standing behind two generations of TLC based SSDs, proving a number of our initial preconceptions of TLC incorrect ? the biggest of which is drive endurance. Unlike cMLC (consumer MLC) which is generally rated at ~3,000 P/E (Program/Erase) cycles, TLC is rated at an estimated ~1,000 ? 1,500 P/E cycles (the actual number hasn't really been revealed by Samsung). While it's easy to base assumptions of an SSD's endurance on the NAND's P/E cycles, this is actually a very bad measure of a SSD's total endurance. Endurance also depends on a SSD controller's write algorithms, write amplification, garbage collection routines, and over-provisioning which is why Samsung is capable of claiming that their TLC based 840 SSDs can do 10GB/day and has ??no workload restrictions?? on their 3 year warranty as well.