What is SLC, MLC, and TLC NAND Flash Memory technology, and how does it influence the lifespan and performance level of a Solid State Drive (SSD)?

We’re willing to bet most customers have never asked themselves this question when searching the depths of Amazon or Newegg for SSDs.

In fact, most customers probably don’t give NAND Flash Memory a second thought, even though understanding the differences between the three types could save them money in the long run and significantly improve their device’s performance.

“How is that?” you might ask.

Each type of NAND yields its own advantages and disadvantages, which affects factors like price, longevity, overall performance, and more. So, what should you be aware of to make an informed decision?

Well, it starts with asking yourself three questions.

Still have questions about SSDs? Check out our comprehensive SSD guide to learn more about what they are and how they can improve your setup!

#1. What Is NAND Flash Memory Technology? 

Flash memory is a non-volatile solid-state storage medium, meaning it relies on electronic circuits (as opposed to mechanical moving parts, like HDDs) to store and retrieve your information. The term “non-volatile” simply means it doesn’t require power to retain your data.

The cornerstone of all NAND Flash products is the Flash memory cell (more on these below). Flash cells are housed in integrated circuits (IC), also known as semiconductor wafers or simply “chips.

How your data is stored

SLC MLC & TLC Binary Digits

Data, at its most fundamental level, breaks down into bits — or binary digits (0 , 1) — as seen in the diagram above. Bits represent an electrical charge contained within the cell, which can be switched on (1) or off (0) depending on how much voltage is applied to the cell via its source line.

The cell’s capacity to store bits is what distinguishes one NAND Flash memory element from another, hence the three terms you regularly see in product descriptions:

  • Single Level Cell (SLC)
  • Multi Level Cell (MLC)
  • Triple Level Cell (TLC)

So, an SLC memory element can store one bit, and MLC and TLC can store two or more bits.

Need to brush up on your NAND Flash? Our NAND Flash Technology guide covers the basics of NAND Flash memory cells and the technology that sustains your SSD.

#2. How Does NAND Flash Affect Flash Products?

The cell’s capability to store bits affects everything from the drive’s capacity and transfer speeds to its lifespan and power consumption.

In general, the lower the cell density, the higher the endurance and speed. However, this also means less capacity and a painful price tag.

A bit confused? No worries. We’ve provided a chart below that highlights the general specs of each Flash memory type so you can get a basic idea of what factors set them apart:

NAND Flash Triangle Chart

Some factors explained:

Speed: This refers to transfer speeds, or how fast data is transferred from the host device to the SSD.

Price: The price of a drive ultimately trickles down to its cell density. For example, SLC is the most expensive because it only stores one bit per cell (meaning it has less density), allowing for faster transfer speeds and greater reliability, even at high temperatures that exceed an MLC or TLC’s operating range.

P/E Cycle: Short for Program/Erase Cycle, the P/E Cycle translates to a drive’s endurance. When cell blocks write, erase, and rewrite data, an electrical charge damages the oxide layer of the cell’s floating gate transistor. Over an extensive period of P/E cycles, affected blocks are rendered useless, as they can no longer hold a charge.

eMLC: Generally, MLC NAND is ideal for consumers. Enterprise Multi Level Cell (eMLC) was engineered to accommodate enterprise-level demands at a more agreeable price. The main underlying difference between the consumer and industrial MLCs is the P/E Cycle.

So, how can you apply this knowledge to your next Flash purchase? This leads us to our third question.

#3. Which NAND Flash Memory Is Right For Me?


Based on our chart, we can draw some conclusions:

  • SLC, due to its price and performance level, is better for enterprises
  • MLC performs better and is more expensive than TLC, but both are recommended for consumers
  • TLC is the cheapest drive, but requires the most power

We can strike out SLC and eMLC, as these are far too expensive for consumers. That leaves us with MLC and TLC. Both types of drives are recommended for consumers, so how do you know what’s right for you?

Generally, it’s safest to start with how many Gigabytes (GB) you require. For most end users, a capacity between 240-500GB will suffice.

If you want to be certain of how many GB you need, ask yourself the following questions:

  • What’s the total/approximate capacity of my current hard drive? 
  • How full is my current drive?

You want the same amount of capacity (or more) with a new drive. You also want to ensure you can transfer over all your current files to your new drive, too.

Now that you’ve determined how much capacity you require, you should think about what you expect out of your SSD.

To answer this, ask yourself a few more questions:

  • How often do you add new media files to your computer?
  • Do you use your computer for intensive gaming, photo or video editing?

Media files are large and take up a lot of space. If you’re constantly adding photos, videos, and renderings, you’ll need the right capacity and high R/W speeds.  If you’re not running resource heavy applications, then you don’t need the fastest drive available.

So, what does this mean for you?

Your answers to the questions above indicate what type of SSD you should invest in. To make the choice a little easier, Silicon Power offers TLC and MLC drives.

Both the Silicon Power Ace TLC SSD series and the Silicon Power Slim S60-S80 MLC SSD series are competitively priced, reliable consumer drives.

For those wishing to simply increase boot and load speeds for an improved browsing experience, our TLC drives are the best option.

Anyone constantly uploading, saving, rendering, and downloading new files for work purposes will burn out their drive at a much faster rate, in which case we’d recommend our MLC series.

Again, it all depends on your needs. Next time you’re looking for an SSD, ask yourself the right questions so you can make the best decision for your device and your wallet.

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