Understanding Read, Write, and Mixed Use SSDs: Key Differences Explained

Why are Solid State Drive Types Important?

When choosing the best suited SSD for your infrastructure, it is important to take in account their type, their form factor and their interface connection. SSD types range from: read intensive, write intensive or mixed use SSDs. For form factor and interface connection we have SATA, SAS, M.2, and NMVe Solid State Drives.

Whats is Drive Writes per Day (DWPD)?

DWPD is a measurement metric for SSDs that is based on how many times an SSD can rewrite itself (its entire capacity) per day over it warranty period without wearing or over work the SSD. Read intensive drives offer a range of 0.2 to 0.5 DWPD which is considered the low standard. Mixed use SSDs will range from 0.5 to 1 DWPD and the middle standard and write intensive drives 1 to 3+ DWPD.

What is the Purpose of SSD Types?

1. Read Intensive SSDs: Perform at their best in environments where reading data is more crucial than writing data. The optimization of these drives is focuses on creating cost-effective solutions for readind data in intensive workloads. Read Intensive SSDs are mainly used for tasks such as: web hosting, database querying, asset loading, and content delivery among other tasks.
2. Write Intensive SSDs: Performance is heavily tackled on the side of writing data rather than reading. These types of solid state drives offer the best endurance, reliability and longevity levels out of all other types of SSDs. These types of drives offer high speeds for data storage, which are suitable for real-time analytics, video surveillance systems, scientific simulations and among other data write specific tasks. Write intensive SSDs offer the biggest metric of DWPD ratings, meaning these SSDs can rewrite their data multiple times a day without wearing themselves out compared to the other types of solid state drives; thus, proving to be the most reliable drives in the market.
3. Mixed Use SSDs: These drives are the middle ground between write intesive and read intensive SSDs. If we need a solid state drive that can tackle both reading and writing data, then mixed SSDs is the best and most common option in the market. Performance is consistent, does not lean more on data writing or data reading. These are the best type of drives for workloads such as, virtualization, database server storage with high transaction workloads, private cloud storages, AI/ML, and online game servers amongo other workloads. DWPD ratings fall between read intensive and write intensive drives, but ensure that at the least 1 DWPD can be done within the day, with the tradeoff of having lower writing speeds than write intensive drives and lower reading speeds than of read intensive SSDs.

SSD Form Factors and Interfaces

Adding to the types of SSDs, another topic to consider is the form factor and interface of solid state drives. This topic adds a whole new branch of consideration when looking for an SSD for your infrastructure. Form factors such as SATA, SAS, NVMe, and M.2 tackle different markets and different industries, each one having its own benefits and drawbacks.

Conclusion

1. SATA SSDs: With being seen as a legacy design, SATA SSDs are still the most used and budget friendly SSDs in the market. Systems nowadays by default offer SATA interface ports, in order for this drives to be connected to the system. SATA SSDs tend to be a cheaper upgrade to using HDD (Hard Disk Drives), while also offering better speeds than hard drives at 6GB/s. It is best suited for older systems, general purpose computers, consumer or gaming computers, that need an upgrade from a HDD or simply a capacity upgrade from a lower capacity SATA drive.
2. SAS SSDs: Tackling higher speeds compared to the SATA interface, SAS SSDs focus more on the enterprise level systems as they offer the high metrics of DWPD with drives having a 3 DWPD rating. They also offer speeds between 12GB/s and 24GB/s in transfer speeds, faster than SATA SSDs. SAS drives offer more reliability and performance for heavy workloads, high data availability and throughput. Interface includes dual-port connecctions, bets compatibility with RAID controllers for Mirroring, and parity of your data, and has better read intensive performance.
3. M.2 PCIe SSDs: Different from SAS and SATA drives that depend on power connected straight from the system's power supply, M.2 drives are non volatile and are connected via a x4 PCIe lane port normally integrated on the system's motherboard, or it can also be used by using a PCIe card connected to the motherboard's PCIe slot such as Dell's BOSS cards or Supermicro's NVMe PCIe cards. This form factor is the smalledst of all the current technologies, and provide faster speeds compared to SATA and SAS at a much smaller physical form. However, depending on the system's PCIe generation, these drives can have different speeds based on compatibility with the latest PCIe generation being PCIe Gen5.0 as of 2025.
4. NVMe SSDs: Current top of the line SSD technology, has similarities with M.2 drives, such as using PCIe interface, it is the ultimate fastest data transfer drive techonology in the market. With fast response times, reduced heavy transfer and loading speeds, NVMe drives are the drives needed for the latest and heaviest workloads. Often used as boot drives for operating systems, video editing, animation, high transaction database connections and other performance based tasks.