What Is SSD Endurance and How Does It Affect Your Drive?

Summary: The lifespan of an SSD, known as SSD endurance, is measured in terms of the number of program/erase (P/E) cycles its NAND flash memory can withstand before it fails. It is typically expressed in Terabytes Written (TBW) and Drive Writes Per Day (DWPD). Factors such as the type of NAND flash memory, DRAM cache size, and wear leveling algorithms affect SSD endurance. While higher TBW ratings indicate longer life, actual performance can vary significantly based on real-world usage patterns.

Over the past decade, Solid-State Drives (SSDs) have become increasingly popular. They are known for their speed, durability, and reliability compared to traditional Hard Disk Drives (HDDs).

However, one important aspect to consider when purchasing an SSD is its endurance. SSD endurance is a measure of how long a drive will last under regular usage, and it directly affects the lifespan of your SSD.

This guide provides a comprehensive overview of SSD endurance. We analyze how it is measured, and the factors that influence it.

We cover:

1. What is an SSD?
2. What is SSD Endurance?
3. Why SSDs Have Limited Write Cycles?
4. What Factors Affect SSD Endurance?
5. Does Higher TBW Guarantee SSD Longevity?
6. FAQs

What is an SSD?

An SSD, or Solid-State Drive, is a type of non-volatile storage device. Unlike hard disk drives, SSDs have no moving parts and rely on flash memory. This technology allows for faster data access speeds and greater reliability.

What is SSD Endurance?

SSD endurance measures the lifespan of an SSD in terms of how much data it can write over time. It is usually expressed as Terabytes Written (TBW) and Drive Writes Per Day (DWPD). Endurance can vary significantly from manufacturer specifications due to factors like workload type (random versus sequential writes and block size), and the amount of extra storage (overprovisioning) on the SSD.

We explain these concepts in more detail below.

1. TBW 

TBW stands for Terabytes Written. It’s a metric used to measure the lifespan of a solid-state drive (SSD). TBW indicates the total amount of data that can be written to the SSD before it is no longer safe to store data on it.

When new data is written to an SSD, an existing data block needs to be erased first. Repeated program/erase (P/E) cycles degrade the oxide layer of the NAND flash memory cells. Over time, this wear and tear reduces the cells’ ability to store data effectively.

TBW is therefore, the total number of terabytes that an SSD can write to its cells before it reaches its end-of-life (EOL). Please note that the SSD might not fail at its end of life, but it becomes unsafe for secure storage of data at this stage.

For example, the Crucial BX500 1 TB SSD has a 240 TBW endurance. This essentially means you can write 240 TB of data before it fails. It is not an exact measurement but an estimate. That is why manufacturers still prefer to give a warranty in years and not TBW.

2. DWPD 

Drive Writes Per Day (DWPD) is a metric used to estimate the endurance of a solid-state drive (SSD).

It’s calculated by dividing the TBW by its rated endurance.

DWPD shows how many times the entire capacity of the SSD can be written each day during its warranty period.

In the above case, the Crucial BX500 1 TB SSD has a TBW of 240 TB and a warranty of 3 years. Its DWPD would be:

[240 TB / (3 years * 365 days)] = 0.219 TB/day or 219 GB/day

In simple words, if you write 219 GB daily, expect the SSD to last 3 years.

Why SSDs Have Limited Write Cycles?

Solid-state drives (SSDs) use flash memory to store data. SSDs are incredibly fast and reliable, but they have a finite lifespan. This limitation stems from the way flash memory works.

The Structure of Flash Memory

Flash memory is composed of trillions of tiny cells of silicon. Each cell can store data (as 0 and 1).

An SSD’s smallest unit is a page, typically 4 KB in size. A page consists of multiple cells. Several pages are grouped to form a block.

A block typically measures 512 KB. There are millions of blocks on an SSD.

The Writing Process

When you write data to an SSD, the controller must first erase the entire block before it can write new data. As the cells inside a block are written and re-rewritten, they constantly switch between 0 and 1.

Why does an SSD degrade? 

This degradation occurs when a cell is erased, and some of the stored charge can become trapped in the cell’s structure, making it difficult to write new data.

In short, there is a finite number of times we can write data before an SSD begins to fail.

What Factors Affect SSD Endurance?

SSD endurance is influenced by several key factors. Understanding these factors can help you choose the right SSD.

1. Type of NAND Flash Memory: The type of NAND technology has a large role to play in SSD endurance. Newer technologies like quad-level-cell (QLC) are cheaper but offer lower P/E counts. A lower P/E count translates to a shorter life span.

2. DRAM Cache Size: There is Dynamic Random Access Memory, DRAM, inside the SSD. Bigger DRAM size acts as a buffer for write operations, which helps prolong the SSD’s life.
3. Wear Leveling Algorithms: Wear leveling spreads out write and erase cycles across all memory cells. This process helps prolong the life of the SSD by preventing any single cell from wearing out too quickly. Better algorithms mean more SSD endurance.

Does Higher TBW Guarantee SSD Longevity?

No, TBW is not a guarantee but rather an estimate of the drive’s endurance.

While many SSDs can exceed their TBW rating, it is possible for a drive to fail before reaching its TBW limit due to manufacturing defects and hardware failure.

Common issues with SSDs include:

• Failures in electronic components.
• Malfunctions of the controller chip.
• Degradation of flash cells due to regular use.
• Issues caused by power surges or failures.
• Damage to the printed circuit board.

Though SSD technology is very advanced, it is not foolproof. An SSD may fail just after a few months of use because of one or more of the causes we explained above. Thankfully, even if an SSD fails, the data might still be recoverable.

If the cause is logical, you could be able to recover the data on your SSD using Stellar Data Recovery Software. However, in many cases, the SSD failure is because of a physical issue with the drive. In such cases, you need a data recovery service to get back your data from the damaged SSD.

Stellar SSD Data Recovery Service is India’s most trusted SSD data recovery service. We have over 30 years of expertise in recovering data, using cutting-edge technology.

Whether it’s an M.2 SATA SSD, PCIe NVMe drive, or any other type of SSD, our team of experts can recover your data safely and securely. We can recover data from Western Digital, Seagate, SanDisk, Kingston, Samsung, and any other brand.

Contact us today to recover your data swiftly and with 100% confidentiality.

We hope you found this article about SSD endurance informative. We welcome your questions and suggestions. Comment in the box below or write to us with your queries and suggestions. Now we answer a few questions readers have asked us.

FAQs 

1. What is SSD over-provisioning? 

When an SSD is manufactured, a small percentage of its total storage capacity is set aside for over-provisioning. This space is utilized by the SSD controller to perform garbage collection and wear leveling.

It is more important for write-intensive SSDs and not read-intensive ones. At the consumer level, however, SSDs are not sold in that manner and an average of 8-12% space is set aside for over-provisioning.

2. Which is the fastest SSD currently available for consumers? 

Our research shows that Crucial T705 2TB PCIe Gen5 NVMe M.2 SSD (2024) with speed of up to 14,500 MB/s is the current fastest SSD. It is however, not launched in India yet. The Crucial T700 with a speed of up to 12,400 MB/s is available.

These are for use in gaming PCs and 3D graphics workstations and cannot fit inside a laptop.

For laptops, Samsung 990 EVO SSD 2TB, PCIe 5.0 x2 M.2 2280 with speeds up to 5,000MB/s is the best model available.

3. How can I check the current endurance of my SSD?

Most SSDs support SMART (Self-Monitoring, Analysis, and Reporting Technology). You can access this data using Stellar Drive Monitor and check health and performance in real time.

Moreover, it lets you clone your hard disk immediately and without any hassle after receiving a health warning.