Understanding the Different Types of Memory used in SSDs
Why are solid state drives superior to the traditional spinning hard drives? If you have used both types of hard drives, you will notice that the former have faster load times, the overall efficiency is better, and they are more durable than the traditional variant. These are enough reasons to give SSD an edge over traditional hard drives.
Before moving on to the different memory cells of solid state drives, let’s take a look at the anatomy of an SSD:
• DDR memory – it contains an insignificant amount of volatile memory that is used to cache information to help during future access. However, not all SSDs have DDR memory.
• NAND flash – these contain chunks of non-volatile memory where your data is usually stored.
• Controller – the firmware used in the controller helps to manage the SSDs and is also the main link between your computer and the NAND flash.
Now that you have an idea of what’s inside an SSD, here are the different types of memory used in SSDs that you should know about:
SLC or Single Level Cell Flash operates on a single bit. You can keep it on or switch it off while charging. It is one of the most important memory cells of SSDs because it provides the most accurate reading and writing data. SLCs also last longer than other memory cells during reading and writing cycles.
The approximate reading and writing life cycle of SLCs are expected to last between 90,000 and 100,000. Its high-performance levels, accuracy, and lifespan have made it the leading memory cell in the enterprise market.
Also, its ability to operate in high temperature ranges gives an edge over other cells. SLCs are widely used in industrial machines where workloads require a broader reading and writing cycle range.
MLC or Multi Level Cell has the ability to use one cell to store multiple bits of data. Compared to single level cell, this one has a lower manufacturing cost. Since the cost involved in flash production is low, the overall price of MLC automatically comes down.
However, the data reading and writing life is lower compared to SLCs. MLC flash is often preferred by customers because of the low price but if you want a better reading and writing life, you will have to rely on SLCs. The reading and writing life is as low as 10,000 per cell. So, you shouldn’t expect a bigger lifespan from MLCs. These memory cells are mostly used in the gaming industry and for daily-use products.
TLC or Triple Level Cell is the cheapest form of flash available. Unlike SLC and MLC that uses single bit and multiple bits to store data, TLC stores data in 3 bits per cell. However, it has a very low reading and writing life cycle that ranges between 3,000 to 5,000 cycles per cell.
One of the advantages of the using TLCs is that it is cheaper to manufacture than MLC or SLC and that’s why the overall price of SSDs using TLC also comes down. TLCs are not meant for industrial use as they don’t have a broader range of reading and writing life cycle. Triple level cells are used in everyday consumer gadgets like netbooks, email machines, and tablets.
SSD manufacturers have not limited the memory cells to SLC, MLC, and TLC. They have introduced another memory cell that uses four bits per cell in a data center. This is known as QLC or Quad Level Cell. It uses the NAND technology to operate and has already been used by leading SSD manufacturing companies. One of the advantages of using QLC is that it offers more storage capacity than TLC or MLCs. The modern quad-level cells come with 64-layer 4 bits to produce 33% higher array density than TLCs.
A big difference between QLC and TLC is that the former can be used to handle enterprise workloads like artificial intelligence, real-time analytics, and big data processing.
However, the makers have made sure that it is also usable in everyday consumer products like computers and laptops.
How to choose from the different types of memory used in SSDs – SLC, MLC, TLC, and QLC?
Every memory cell of SSDs has their own pros and cons but from the point of view of an IT buyer, you should look to choose the highest performing solid state drive to make the most of the memory cells used. Your basis for choosing the memory cells should be based on the type of performance you want from the gadget that they will be used on.
If you are looking for high-performance, SLCs and QLCs will be the ideal choice. But if you are looking for cheaper alternatives, then you have TLCs and MLCs to choose from. Don’t always base your choice according to their manufacturing costs.
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