Enterprise multi-level cell (MLC) SSD, or eMLC as vendors now call it, uses less expensive flash memory but adds cache, special firmware for write amplification, error correction code (ECC) in the controller and wear-leveling software to evenly spread data writes across the media to increase reliability and performance.

As the SSD software becomes more sophisticated, the reliability and performance levels of MLC-based drives are creeping closer to that of SLC-based products.

Several leading storage hardware vendors have come out with MLC-based SSDs in recent month. Israeli start-up Anobit Technologies, as well as OCZ and Micron, have also announced enterprise-class SSDs based on MLC NAND technology.

IBM it has begun using STEC's MLC SSDs in its high-end DS8800, DS8700 arrays and its midrange Storwize 7000 boxes.

According to market research firm Gartner, shipments of SSDs for servers and enterprise storage systems will increase from 324,000 in 2009 to 6.3 million units in 2014 and will grow in terms of revenue for vendors from $485 million to $3.6 billion during the same period.