SSD MLC cells move into the enterprise high end

MULTI-LEVEL CELL (MLC) flash-based solid state disk drives were, until recently, considered more of a consumer device choice, since their read and write performance, as well as expected lifetime in terms of number of writes before the cell is gone, were quite a bit behind the standard SLC (Single Level Cell) devices seen in entereprise class SSD units.

However this year saw a massive change, as MLC gained both in performance and reliability, while keeping the capacity and price advantage it offers over SLC. The final blow was Intel's own Series 710 enterprise SSDs shown at the IDF event in September. The new SSD drives, with up to 300GB capacity in a standard 2.5in form factor, completely replaced the previous SLC-based range.

What changes enabled this move? Improvements in the controllers and write leveling algorithms drastically reduced the write penalty while keeping good bandwidth and latency, and the silicon design of the cells themselves was sufficiently improved to further come closer to SLC performance and reliability.

With up to 38,500 IOPS in reading and 2,700 IOPS when writing (4K blocks), they stack up well to their SLC-based brethren, and you still get a 300GB enterprise drive for less than $2,000 apiece. For that, you also get decent latency at 75µsec for reads and 85µsec for writes, but unfortunately the bandwidth is still limited by the old 3Gbits/s SATA-II Interface here, reaching 270MB/s for reads and 210MB/s for writes. Power consumption, at 2.7 watts in active mode, is very decent though.

It seems a bit odd that Intel didn't go with the brand new 6Gbits/s SATA3 interface, which its competitors in the SSD market have already actively embraced. On the other hand, Intel might be after something even more attractive in its next line of high-end SSD drives.