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Benchmarks

Storage benchmark

The storage benchmark measures your drive's read and write performance for both sequential and random access patterns. The combined result produces your storage score, which reflects how quickly your system can load, save, and access data on disk.

What the storage test measures

The storage benchmark runs four tests that cover the two main types of disk access.

Sequential read and write

Sequential tests measure throughput when reading or writing large contiguous blocks of data. This pattern represents workloads like copying files, loading large applications, video editing with large media files, and reading or writing disk images.

Random read and write

Random tests measure how quickly the drive responds to small, scattered read and write operations. This pattern represents everyday workloads like booting the operating system, launching applications, loading game assets, and running databases.

Random performance determines how responsive your system feels during normal use. Even a fast sequential drive can feel slow if its random access performance is poor, because most everyday disk activity involves many small random operations rather than sustained large transfers.

Test methodology

Each test runs for a fixed duration using asynchronous I/O, measuring how much data the drive transfers in that time. The four tests use specific block sizes and queue depths chosen to reflect their real-world counterparts:

Test

Block size

Queue depth

Access pattern

Sequential read

4 MB

8

Contiguous

Sequential write

4 MB

8

Contiguous

Random read

4 KB

1

Random

Random write

4 KB

1

Random

Sequential tests use large 4 MB blocks with a queue depth of 8, allowing the drive's controller to optimize for sustained throughput — similar to how file copies and media playback access data. Random tests use small 4 KB blocks with a queue depth of 1, reflecting the small, scattered I/O operations of application launches, OS activity, and database queries.

All platforms use the same test patterns and parameters with platform-native asynchronous I/O, ensuring that results are comparable across operating systems. Test data is written to and read from your system's temporary directory by default.

Testing specific drives

By default, Novabench tests the drive where your system's temporary directory is located, which is typically your primary (boot) drive. If your system has multiple drives and you want to test a different one, you can change the test path in Novabench's settings to point to a directory on the target drive.

This is useful for:

  • Comparing drives: test each drive individually to see how they compare
  • Verifying a new drive: confirm that a newly installed SSD delivers the expected performance
  • Diagnosing a slow drive: if a specific drive feels slow, benchmark it to see whether performance matches the manufacturer's specifications

Note

The test path must be writable. Novabench creates and deletes temporary test files during the benchmark. If the target directory is read-only or on a network share, the test will fail or produce inaccurate results.

How the storage score is calculated

The storage score is derived from both sequential and random performance (for both read and write). The formula applies a power curve that reflects the diminishing practical impact of extremely high sequential speeds: the jump from a hard drive to a SATA SSD produces a large score improvement, while the jump from a fast Gen 4 NVMe to a faster Gen 5 NVMe produces a smaller (though still very measurable) improvement.

Factors affecting storage scores

Drive health and capacity

  • Free space: SSDs perform best when they have ample free space. A nearly full SSD has fewer blocks available for wear-leveling and garbage collection, which can reduce write speeds. Keep at least 10% to 20% of your drive free for optimal performance.
  • Drive age and wear: SSDs have a finite number of write cycles. A heavily used SSD may show reduced write performance as it ages. Most SSDs report their health status through S.M.A.R.T. data, which Novabench displays in a tab with the storage test results.
  • Fragmentation: on traditional hard drives, file fragmentation forces the read head to move between scattered blocks, reducing both sequential and random performance. SSDs are not affected by fragmentation because they have no moving parts. Operating systems run background de-fragmentation operations on HDDs to reduce the impact of fragmentation, and it is generally no longer considered a practical performance concern.

System conditions

  • Background disk activity: cloud sync services (OneDrive, Dropbox, iCloud), antivirus scans, system updates, and indexing services all generate disk I/O that competes with the benchmark. Close or pause these services for the most accurate results.
  • Thermal throttling: some NVMe SSDs throttle performance when they overheat, especially M.2 drives without adequate cooling. If your storage scores drop during multi-iteration runs, thermal throttling may be the cause.
  • Interface limitations: a fast NVMe SSD installed in a PCIe 3.0 slot will be limited to Gen 3 speeds, even if the drive supports Gen 4. Check your motherboard specifications to confirm the slot supports your drive's maximum speed.

External drives

Benchmarking external drives is possible by changing the test path, but results depend on the connection interface:

  • Thunderbolt 4/3: up to 3,000 MB/s, suitable for external NVMe enclosures
  • USB 3.2 Gen 2x2: up to 2,000 MB/s theoretical
  • USB 3.2 Gen 2: up to 1,000 MB/s theoretical
  • USB 3.0 (Gen 1): up to 500 MB/s theoretical
  • USB 2.0: limited to approximately 40 MB/s

The connection interface, cable quality, and enclosure controller all affect external drive benchmark results.