Solid state drives (SSDs) have become increasingly popular in computers due to their fast speeds and lack of moving parts. Some users choose to configure multiple SSDs in a RAID 0 array to try and achieve even faster performance. But does combining SSDs in RAID 0 actually provide any benefit?
What is RAID 0?
RAID stands for “Redundant Array of Independent Disks”. It is a method of combining multiple physical disk drives into one logical drive to provide increased performance, capacity, or redundancy.
RAID 0 is one of the most basic RAID configurations. It involves striping data across two or more disks with no parity or duplication. This means the total storage capacity of a RAID 0 array is equal to the sum of the capacities of its individual disks. For example, two 500 GB drives in RAID 0 would create a single 1 TB logical drive.
The main benefit of RAID 0 is increased performance. By splitting and distributing data across multiple disks, read and write operations can be performed in parallel. This means throughput is multiplied compared to using a single disk alone. For example, two SSDs in RAID 0 can deliver close to double the read and write speeds of a single SSD.
The downside is RAID 0 provides no data redundancy. If one drive fails, all data on the array will be lost. For this reason, RAID 0 is primarily used in non-critical storage environments where performance is the priority over data security.
Do SSDs benefit from RAID 0?
When it comes to SSDs, the benefits of RAID 0 are less clear. There are several factors to consider:
- SSD performance is already very fast compared to hard disk drives (HDDs). High-end NVMe SSDs can deliver sequential read/write speeds over 3,000/2,000 MB/s and random read/write speeds up to 750,000/700,000 IOPS.
- SSD performance is limited by the drive’s controller and NAND flash memory. RAID 0 improves performance by allowing parallel operations across multiple disks. But with SSDs, the controller and flash are already very fast – often faster than the drive connectors like SATA or PCIe 3.0 x4 can support.
- There is no seek time benefit with SSDs. RAID 0 helps HDDs by distributing data across multiple platters and read/write heads, decreasing average seek time. SSDs have no seek time penalty.
- SSDs already saturate the bandwidth of most consumer computing interfaces. For consumers using SSDs with SATA 3.0 or PCIe 3.0 x4, a single SSD can already deliver speeds that max out the interface bandwidth limits (600 MB/s for SATA 3.0 and ~4 GB/s for PCIe 3.0 x4). Adding a second SSD in RAID 0 may not provide any additional performance benefit if the interface is already saturated by a single drive.
Because of the above factors, most benchmark tests find that RAID 0 provides little to no real-world improvement to SSD performance for typical consumer workloads. The differences tend to be small and only observable in certain niche scenarios.
When RAID 0 does help SSD performance
While most consumer uses won’t see a notable performance gain with SSD RAID 0 arrays, there are some cases where multiple SSDs in RAID 0 can be beneficial:
- PCIe 4.0 or faster interfaces – Next-gen PCIe 4.0 and upcoming PCIe 5.0 provide double or quadruple the bandwidth compared to PCIe 3.0, which a single SSD may not be able to saturate. RAID 0 can allow hitting those higher interface limits.
- Very heavy workloads – In niche scenarios with extremely heavy workloads involving massive files, like 4K video editing, scientific data analysis, or database applications, RAID 0 can provide a noticeable speedup by distributing data across multiple SSDs.
- Enterprise environments – For mission-critical enterprise servers and data centers that demand the absolute highest performance, SSD RAID 0 can help eke out extra speed.
But for general consumer use cases like booting an OS, launching applications, file transfers, and gaming, single SSDs already provide exceptional performance. RAID 0 offers little real-world benefit in most standard use cases.
Potential downsides of SSD RAID 0
Beyond the questionable performance gains, there are also some potential downsides to keeping in mind with RAID 0 SSD arrays:
- No fault tolerance – As mentioned earlier, RAID 0 provides no data redundancy. If one drive fails, all data on the array is lost. Important data should be regularly backed up.
- Increased chance of failure – The probability of array failure is equal to the sum of failure probabilities for each drive. More drives means higher likelihood of failure.
- Extra costs – Building a RAID 0 array requires purchasing multiple matched SSDs, along with a RAID controller if not using a motherboard with RAID support built-in.
- Complexity – Configuring and managing a RAID array adds complexity versus using standalone SSDs. Software RAID management is also generally preferred over hardware RAID for SSDs.
Alternatives to SSD RAID 0
Given the limited benefits and added risks, SSD RAID 0 arrays are generally not recommended for most consumer use cases. There are a few alternatives to consider instead:
- Single large SSD – A better performance per dollar option is often to simply buy a single higher capacity SSD rather than trying to combine smaller SSDs in RAID 0.
- M.2 NVMe SSD – Switching to a faster M.2 NVMe SSD over SATA can provide a bigger performance boost than RAID 0 for many workloads.
- Additional HDD storage – If more storage capacity is needed, adding an additional HDD for data storage is cheaper than buying another SSD for RAID 0.
Conclusion
While RAID 0 can provide big performance benefits with traditional hard disk drives, the advantages are much smaller for high-speed SSDs. For typical consumer use cases, a single SSD will usually provide great performance on its own without the risks and complexity of RAID 0.
RAID 0 SSD arrays only tend to help in niche cases like cutting-edge PCIe 4.0/5.0 builds demanding maximum interface bandwidth or very heavy workloads that can leverage parallel storage I/O. For general desktop and gaming use, there is little measurable benefit to combining SSDs in RAID 0 versus using a single fast NVMe SSD.
