According to a new study that span over a period of six years, it appears that high-end SSDs based on single-level cell (SLC) NAND flash memory are not more reliable compared to much cheaper SSDs based on multi-level cell (MLC) NAND SSDs.

Based on 10 different models of enterprise SLC-based and consumer MLC-based SSDs, three different memory types, including SLC NAND, MLC NAND and eMLC NAND and spanning over a period of six years, the study titled "Flash Reliability in Production: The Expected and the Unexpected," made by professor Bianca Schroeder of the University of Toronto, and Google's Raghav Lagisetty and Arif Merchant, shows that SLC-based enterprise SDDs are no more reliable than MLC-based consumer SDDs.

The study also notes that raw bit error rate (EBER) is much better in measuring reliability compared to uncorrectable bit error rate (UBER) and that the real-world reliability of SSDs is better compared to HDDs, making SSDs less likely to break compared to HDDs.

Another interesting conclusion in the study is that SSDs reliability is affected by age rather than usage, with bad blocks in new SSDs are a common sight and with 30 to 80 percent of SSDs developing at least on bad block, with 2 to 7 percent of them developing one bad chip in the first four years of usage.

The paper is quite an interesting read and the full results are quite interesting, showing that SSDs are indeed the future but still have their own set of issues.



Source: ZDNet.com.