Micron has announced that it will deploy triple level cell (TLC) NAND in its 5100 Series, marking the first time any company has used TLC NAND in an enterprise product. Typically, enterprise and many consumer drives are based on multi-level cell (MLC) NAND, which stores two bits of information per cell. TLC drives can store three bits of information per cell, but these drives are typically only capable of a fraction of the program/erase cycles that MLC drives can offer. What makes Micron’s drives different is that the company is using 3D NAND flash instead of traditional 2D (planar) NAND.
Micron isn’t just using TLC — it’s baked in some tricks to make the drives more attractive to the enterprise crowd. For one thing, the entire 5100 Series (5100 Eco, Pro, and Max) are all substantially overprovisioned. The density-focused 5100 Eco has the lowest spare area, at 15% of drive capacity, and the lowest random write speeds, but is expected to sell for 45-55 cents per GB. At the other end of the spectrum you’ve got the 5100 Max, which is overprovisioned by up to 60% and is expected to sell for 65-75 cents per GB (capacities on the 5100 family range from 240GB – 1920GB depending).
The use of TLC NAND might seem surprising, but it actually tracks advances we’ve seen from other manufacturers. Micron hasn’t revealed exactly what process node they’re using, but we know that Samsung fell back to the 40nm node when it built what it calls V-NAND and the longevity of its TLC NAND skyrocketed. TLC from Samsung is rated up to 20,000 P/E cycles, which actually exceeds the typical values on traditional MLC NAND by a substantial margin.
Micron is still getting its toes wet in the 3D NAND business, but the company has another trick up its sleeve — its 5100 Series can be reconfigured on the fly to allocate more or less space as “spare” NAND in the event of NAND failure. Allocate enough available capacity to spare area, and the drive will automatically adjust its performance to match the characteristics of the higher-end drives in Micron’s family.
This is a win-win, as far as Micron is concerned. If you buy a 5100 Eco drive at 1920GB and then repartition it to serve as a 5100 Max, you’ll be giving up 45% of your drive storage to do it (remember, the Eco starts with a 15% spare area partition, while the Max has a 60% spare area partition). This makes the Eco more expensive, in terms of cost-per-GB, than the faster Pro or Max. Customers who adjust their own drives and find they need better performance will likely gravitate towards the upper product tiers, while customers who already brought a Max and don’t need the extra performance can reconfigure the drives and take advantage of the additional capacity. Either way, Micron makes money, and customers get hardware that more closely fits their needs.
As we discussed last week, NAND flash prices are expected to move higher this quarter thanks to early 3D NAND ramps and general strong demand for notebooks. Prices should drop again in 2017 as the market cools down.