The world has largely transitioned away from hard drives, with the superiority of SSDs being widely recognized. Most people understand that SSDs significantly outperform HDDs, and that NVMe SSDs are faster than their SATA counterparts. When purchasing an SSD, users typically focus on key specifications like the interface (SATA/NVMe), PCIe generation (Gen3, Gen4, Gen5), capacity, and the advertised read/write speeds. However, there are less obvious but equally important specifications that can significantly impact an SSD's real-world performance. These relate to the quality of the components inside the SSD, and it's crucial to consider them alongside the more obvious specs when choosing a new drive.
Endurance
Longevity is just as critical as speed when selecting an SSD. No one wants a fast SSD that fails after just a year or two. SSDs, like all electronic devices, have a finite lifespan, so it's important to check an SSD's endurance rating before making a purchase. While SSDs from reputable brands generally have a low risk of early failure, endurance should still be on your checklist. Even with heavy daily usage, an SSD rated at 600TBW should last 5 to 6 years. Endurance is measured in Terabytes Written (TBW), indicating the total amount of data that can be written to the SSD over its lifetime. For example, a 1TB SSD with a 600TBW rating can handle up to 600TB of data before failure becomes likely.
Type of NAND Flash
SSDs are built with NAND flash memory, which comes in different types depending on the number of bits stored per cell. Single-level cell (SLC) NAND stores one bit per cell, making it the most expensive but also the fastest and most durable. Multi-level cell (MLC), triple-level cell (TLC), and quad-level cell (QLC) NAND store two, three, and four bits per cell, respectively. SLC drives are ideal for environments where longevity is crucial, such as servers, while MLC and TLC NAND are more common in consumer SSDs, offering a balance between cost and performance. QLC NAND is used in high-capacity drives where speed is less critical. If you're buying an SSD for tasks like booting your system or storing games, TLC NAND is a good choice, as it's widely used in high-performance consumer drives.
Controller
The SSD controller is the onboard chip that manages all the drive's operations and handles communication with the system. It plays a significant role in the SSD's performance, efficiency, and reliability. It's worth checking which controller is inside the SSD you're considering, as this can affect data transfer speeds, latency, and input/output operations per second (IOPS). Major brands like Samsung and Intel design their own controllers, while others use controllers from companies like Phison, SMI, and Marvell. While the controller isn't the only factor determining SSD performance, it's an important consideration. You can often find detailed information on controller performance in third-party reviews, so it's worth researching before making a decision.
DRAM or DRAM-less
DRAM acts as a high-speed memory buffer, storing frequently accessed data to speed up certain operations on your computer. If you're primarily interested in gaming, having DRAM on your SSD may not make a noticeable difference, since gaming workloads are usually read-heavy. However, if you frequently transfer large files, DRAM can significantly improve performance. While DRAM-less drives have improved in using system resources as a substitute for DRAM, it's still advisable to choose a DRAM-equipped SSD if the price difference is small. Workloads involving sustained read/write operations, where advertised speeds really matter, benefit most from DRAM.
Random Read/Write Speeds
Instead of focusing solely on the sequential speeds advertised for SSDs, it's also important to consider random read/write speeds. These are more reflective of typical real-world use, such as gaming and general desktop tasks. Random read/write speeds, measured in IOPS, can be harder to find on product pages but are often detailed in third-party reviews. High-end SSDs like the 990 Pro can reach up to 1.6 million IOPS for random reads and 1.5 million IOPS for random writes, while other models like the WD Black SN770 can achieve around 800,000 IOPS. If you're not a professional user who can fully utilize high sequential speeds, paying attention to random read/write speeds is crucial when selecting an SSD.