What is QLC? What is TLC? What are the differences between QLC and TLC? As for QLC vs TLC, which one is the best for the storage application? This post from MiniTool will show you the answer.

Nowadays, hard drives and solid-state drives are becoming bigger and faster since the size of the file has become larger and larger or users have more files to store, such as photos, movies, games, etc. Hence, the hard drive with a larger capacity becomes more popular.

When it comes to larger hard drive capacity, the flash memory would be an essential factor. Current SSDs use the NAND flash storage, whose building blocks are the memory cell. There are base units onto which data is written in an SSD and each memory cell accepts certain amounts of bits. The most common ones include the SLC, MLC, TLC, and QLC. In addition, in the following part, we will show you what the QLC and TLC are and what the differences of QLC and TLC.

Tip: For more information about SSD, you may be interested in this post: Everything You Need to Know About Solid-state drive (SSD) – Guide

What Are QLC and TLC?

TLC, whose full name is the Triple-Level Cell, stores three bits of information per cell. In addition, TLC is the most common type of SSD.

QLC, whose full name is Quad-level cell, stores four bits of information per cell, following in by the convention set by TLC. Prior to its invention, QLC refers to cells that can have sixteen voltage states.


However, what are the differences between QLC and TLC or which one is better for your storage application?

So, in the following section, we will show you the differences of QLC vs TLC.

QLC vs TLC: What Are the Differences and Which One Is Better?

In this part, we will show you some differences of QLC and TLC. You might think that the QLC with four bits per cell is able to replace the TLC, which is with three bits per cell. However, TLC technology has improved in terms of durability and performance to create roles for both types of NAND. Therefore, we will show more detailed differences of QLC vs TLC SSD.

Before mentioning the differences of TLC vs QLC, you need to know how NAND flash affects the performance, endurance and density.

What Is 3D QLC NAND?

In the past, the cells were arranged side by side on a silicon substrate. But later, it is possible to increase density so as to fit more of them on a planar surface. However, it is difficult to scale along the x- and y-axis, manufacturers started organizing cells vertically, three-dimensionally along the z-axis.

Compared with 2D NAND, the 3D has higher density and it can also be written to and erased more times. If a flash is built-in 64 layers- tall, 3D NAND enables 64 times the cell density of planar memory. Thus, more data will be stored and the SSD with 3D NAND will provide a larger storage size.

What Is 3D TLC NAND?

As we have mentioned in the above part, the QLC NAND stores 4 bits of information per cell and has the 16 voltage states, but the TLC NAND stores three bits of information and only tracks 8.

Compared with QLC NAND, TLC has to withstand a higher number of program/erase cycles due to its fewer bits written to per cell.

On the other hand, as for QLC VA TLC, TLC flash is faster than QLC. It turns out that differentiating between twice as many charge states makes QLC more prone to mistakes than TLC flash. Although both technologies employ error-correcting code algorithms to maintain the integrity of your data, the process consumes a greater number of processing cycles on QLC-based drives, hitting write performance especially hard.

QLC vs TLC SSD: Performance

QLC SSDs are designed to augment existing TLC SSD, rather than replacing them. As for the performance of QLC and TLC SSD, we will briefly show you.

The sequential read speed of QLC NAND SSD is just as fast as the TLC SSD, so it is great for read-heavy workloads. However, as for the write performance of 3D NAND vs TLC, the TLC SSD is better than the QLC SSD.

QLC vs TLC SSD: Endurance

Besides the performance, the endurance of QLC and TLC SSD is also an essential factor. Since QLC SSD is rated for fewer program/erase cycles than TLC, write-heavy workloads wear its memory cells faster. So, as for the endurance of QLC vs TLC, the TLC SSD would be better than QLC SSD. However, the durability of TLC is still lower than the MLC and SLC.

QLC vs TLC SSD: Storage Size

Apart from the performance and endurance of QLC vs TLC SSD, the storage size would be another essential factor. QLC technology can currently achieve a capacity of 768 Gb per flash particle, which can reach up to the maximum.

For example, if an SSD uses eight pieces of such flash particles, the storage size of QLC size can reach up to 12TB which enables you to store a lot of files and data.

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QLC vs TLC SSD: Price

When choosing an SSD, the budget would be also taken into consideration. As for the QLC vs TLC NAND SSD, the price of QLC SSD would be cheaper. And TLC SSD is also cheaper than SLC or MLC.

the performance of QLC and TLC

So, if your budget is limited but you also want to purchase the larger capacity, the QLC or TLC SSD would be a good choice. In addition, even though the performance of QLC may be slower than the TLC SSD, but it is also faster than the old HDD even though with 3D NAND.

From the above QLC vs TLC, you have known what the differences between them and which one is better for you. But as a matter of fact, the QLC and TLC is complement with each other. In the future, 50% of the NAND flash bits shipped will be 3D QLC, with 3D TLC making up most of what’s left.

In addition, QLC NAND will slowly displace some TLC NAND volume now and then and both technologies move forward together.

This post helped me to fully understand what the QLC and TLC NAND are and also showed the differences between QLC and TLC. I’d like to share this post with more friends. Click to Tweet

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How to Upgrade to Large SSD?

From the above part, you can find that the QLC and TLC SSD come to a larger storage size than hard drive. And it also delivers better read and write performance than the original hard drive. With large SSD, users are able to save more files and data, such as photos, movies, videos and so on.

So, some people ask whether there is a way to upgrade the original hard drive to the SSD without data loss. Of course, the answer is positive. In the following part, we will show you how to upgrade hard drive to a large QLC SSD or TLC SSD.

To upgrade hard drive to the large QLC or TLC SSD, you can use a hard drive clone tool. Thus, MiniTool ShadowMaker, which is also a piece of Windows 10 backup software, would be a good choice.

MiniTool ShadowMaker enables you to clone OS to SSD without data loss. So you can use it to clone your hard drive to the QLC or TLC SSD.

Now, here is the tutorial.

1. Click the following button to download MiniTool ShadowMaker or choose to purchase an advanced edition.

MiniTool ShadowMaker TrialClick to Download100%Clean & Safe

2. Install it.

3. Then click Keep Trial to continue.

4. Then click Connect in This Computer to enter its main interface.

click Connect in This Computer to enter its main interface

5. After that, go to the Tools page.

6. Then click Clone Disk to continue.

7. Click Source module to choose the disk clone source. Here, you need to choose the original system disk as the hard drive clone source. Then click Finish to continue.

select the disk clone source

8. Then click Destination module to choose a target disk. Here, you need to select the QLC or TLC SSD as the target disk.

select the target disk

9. Please note all data on the target disk will be destroyed during the cloning process. If there are important files on it, please back up them first.

10. Then the disk clone process will begin. Please do not interrupt the disk clone process until it is finished. The costing time depends on the number of files on the source disk.

disk clone process

When the disk clone process is finished, you will receive a warning message which tells you that the target disk and the original disk have the same signature. So, you need to remove or disconnect either of them. Moreover, if you want to boot computer from the target disk, please enter BIOS and change the boot sequence first.

read the warning message

After all steps are finished, you have successfully upgraded the original hard drive to the QLC or TLC disk.

Bottom Line

To sum up, this post has introduced the differences of QLC vs TLC NAND SSD. If you do not know the differences between them and do not know which one is better, the above content may help you.

In addition, if you have any different ideas of QLC vs TLC or any problem of MiniTool Software, you can share it in the comment zone or please feel free to contact us via email [email protected] and we will reply to you as soon as possible.


Is QLC better than TLC?
QLC or Quad Level Cell, stores 4 bits of data information per cell. Triple Level Cell stores 3 bits of information per cell. So, the storage density of QLC has increased by 33% than the TLC. In addition, the write cycle of QLC NAND SSD can reach up to 1000 times, which is equal or even better than TLC. And QLC SSD is cheaper than TLC SSD.
Is QLC reliable?
The fewer bits per cell NAND cell stores, the faster and more reliable, and more energy efficient the SSD is. Of course, this kind of SSD would be more expensive. As for the reliability, the SLC SSD would be the best and the QLC SSD is the least one.
How long will a QLC SSD last?
For most common SSDs, they are provided a five-year limited warranty. And the QLC SSDs are designed to use in the enterprise, so ordinary users would not worry about the lifespan.
What is a QLC SSD?
QLC SSDs are the latest development of flash technology. Then QLC NAND flash stores 4 bits of data information per cell. QLC NAND can pack a whole lot more data than other types and it also has taken a big hit on drive performance.
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