Thread: The 3-bit MLC malfunctioning

MLC memory, used in most USB drives and SSDs for entry and midrange, should change this year with a move to 3 bits instead of 2, but it seems that the early returns are pretty bad.

2 bits cons 3 bits

Recall that the memory type NAND flash available in two versions, the SLC (Single Layer Cell) and MLC (Multiple Layer Cell). The first stores 1 bit per cell, the second in several stores, usually 2 and version 3 and 4 bits per cell are expected to arrive in 2010. Big advantage of 3-bit versions, the density increases: 1.5 x is stored on the same surface, at a cost similar (or identical). Big disadvantage, it usually loses life by increasing the number of bits and write speeds decrease (it must manage more binary states for a cell, which complicates the detection of voltage levels). And according to a Taiwanese source, the chips "3 bits" of a Korean manufacturer (presumably Samsung) were quickly returned to the founder, because early versions of the chips were "unstable." Problems of throughput, reliability? Nobody knows, but this news - if confirmed - could make a noise: the 3-bit memory was approached to allow SSDs to replace hard drives in the medium term, by reducing prices.