Friday, 25 October 2019

Multi-Layer SSDs: What Are SLC, MLC, TLC, QLC, and PLC?

A Samsung solid-state drive.

Solid-state drives improve the performance of aging computers and turn newer PCs into speed machines. But, when you shop for one, you’re bombarded with terms, like SLC, SATA III, NVMe, and M.2. What does it all mean? Let’s take a look!

It’s All About the Cells

Current SSDs use NAND flash storage, the building blocks of which is the memory cell. These are the base units onto which data is written in an SSD. Each memory cell accepts a certain amount of bits, which are registered on the storage device as 1 or 0.

Single-Layer Cell (SLC) SSDs

The most basic type of SSD is the single-layer cell (SLC) SSD. SLCs accept one bit per memory cell. That’s not a lot, but it has some advantages. First, SLCs are the fastest type of SSD. They’re also more durable and less error-prone, so they’re considered more reliable than other SSDs.

SLCs are popular in enterprise environments where data loss is less tolerable, and durability is key. SLCs tend to be more expensive, and they aren’t typically available for consumers. For example, I found a 128 GB enterprise SLC SSD on Amazon that cost the same as a 1 TB, consumer-level SSD with TLC NAND.

If you do see a consumer SLC SSD, it probably has a different type of NAND and an SLC cache to improve performance.

Multi-Layer Cell (MLC) SSDs

The Intel S3520 Series MLC SSD.
Intel’s S3520 Series MLC SSD. Intel

The “multi-” in multi-layer cell (MLC) SSDs isn’t particularly accurate. They only store two bits per cell, which isn’t very “multi-,” but, sometimes, technology naming schemes aren’t always forward-looking.

MLCs are a bit slower than SLCs because it takes more time to write two bits onto a cell than just one. They also take a hit in durability and reliability because data is written to the NAND flash more often than with an SLC.

Nevertheless, MLCs are solid SSDs. Their capacities aren’t as high as other SSD types, but you can find a 1 TB MLC SSD out there.

Triple-Layer Cell (TLC) SSDs

Read the remaining 17 paragraphs



from How-To Geek https://ift.tt/2BK1wjb

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