The difference is between MLC (unreliable) and SLC (reliable) SSDs. MLC (Multi-Level Cell) SSDs are slightly slower, a lot cheaper, and less reliable than SLC

The difference is between MLC (unreliable) and SLC (reliable) SSDs. MLC (Multi-Level Cell) SSDs are slightly slower, a lot cheaper, and less reliable than SLC (Single Level Cell) SSDs. Fundamentally, an MLC stores more data in each cell (hence the Multi), while an SLC stores 1 bit of data in each cell. There's now all sorts of "eMLC" drives which are pushing the reliability of MLC up towards the SLC levels, but they're not very common yet. http://en.wikipedia.org/wiki/Multi-level_cell http://en.wikipedia.org/wiki/Multi-level_cell