Most solid-state drives are based on MLC flash memory with two bits per cell. Samsung bucked that trend late last year when it released the 840 Series with TLC NAND, which has three bits per cell. Now, according to X-bit labs, Plextor is prepping a TLC-based drive of its own. The SSD will reportedly combine TLC memory from Toshiba with Marvell controller technology and some of Plextor's own special sauce.
X-bit labs cites unnamed "media reports" as saying the drive will push 540MB/s for sequential reads and 450MB/s for writes. Its random I/O rates will be pegged at 80k and 72k IOps for reads and writes, respectively. Those read rates are similar to what Samsung advertises for its TLC-based drive, but the write rates are notably faster. The quickest 840 Series model tops out at 330MB/s for sequential writes and 63k IOps for random writes.
TLC memory typically has slower write speeds than MLC NAND because of the complexity associated with stuffing an extra bit into each flash cell. That makes me a little dubious of the claimed 450MB/s sequential write rate, but we should have a better sense of the drive's performance later this year. X-bit labs says the new TLC SSD is slated for release in the second half of 2013.
When the drive arrives, it should be relatively inexpensive. TLC increases the per-die capacity of flash memory by 50% over MLC NAND, and the higher density effectively lowers the cost per gigabyte. That's why Samsung can sell the 840 Series 500GB for just $300.
Of course, there is one catch. TLC memory has lower write endurance than MLC NAND, and it's still unclear just how much data can be written to drives based on the memory type. The fact that Samsung doesn't quote a total-bytes-written specification for its 840 Series drives doesn't help. We're working on answering that particular question ourselves, though. Stay tuned.
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