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Octal DriveBench

A disk speed test and volume analyzer for macOS. It measures how fast a drive is once its cache runs out, not just the first burst, keeps every run, and puts drives side by side. Free, and a separate download from Octal.

Download DriveBench Support on Ko-fi

Beta · Free · macOS 14 Sonoma or later · Apple silicon and Intel

Octal DriveBench after testing Macintosh HD: sequential write 2,333 MB/s and read 2,420 MB/s, random 4K read and write IOPS, file operations per second, a throughput chart over time, the volume's capabilities, S.M.A.R.T. drive health, and two previous runs

Sequential read and write

The sustained speed, measured once the drive's cache has filled, with the peak and the slowest moment beside it. Fill disk writes until the drive is nearly full, which shows where the cache runs out and can catch a drive that reports more capacity than it has.

Random access

Random 4K reads and writes in IOPS: the small, scattered access that apps and the system generate most of the time.

File operations

Creating, looking up, renaming and deleting thousands of small files, reported as operations per second.

Any volume

Internal and external drives, and network shares mounted over SMB, NFS, AFP or WebDAV.

Bypass cache

Reads and writes bypass the macOS file cache, so they go to the drive rather than to memory, and a write only counts as finished once the drive confirms it's stored. Turn the bypass off to see what apps get with caching in the way.

The test data goes in a hidden folder on the drive and is removed when the test ends, including when you stop it.

  • Test sizes from 1 GiB to 64 GiB, or fill the disk
  • Block sizes from 4 KiB to 4 MiB, starting at the drive's preferred size
  • Random block size from 4 KiB to 64 KiB
  • Any combination of the five tests

Compare runs

Choose two or more runs and see them side by side: two drives, or one drive before and after. The settings each run used are listed under the chart.

Octal DriveBench comparing three runs, Macintosh HD, an SMB server and a Samsung Portable SSD T5, with bars for write, read, random read, random write and file operations

Additional features

Run history

Every run is kept with its chart, its settings and the volume's details at the time.

Share a report

An image of any run, with a QR code back to this page. External drives appear by model and network shares as “SMB Server”, not by your volume name or path, unless you give the report a title of your own.

Drive health

S.M.A.R.T. for the selected drive: a verified or failing verdict, temperature, life used, spare capacity, power-on time, data read and written, and error counts. Save the figures as a text file with Export…

Report titles

Give a report a title of your own. It replaces the drive's name on screen, in comparisons and on images you share.

Volume capabilities

File system, case sensitivity, preferred I/O and block size, name and path limits, and support for sparse files, cloning, snapshots, hard links, symlinks and extended attributes.

Built into Octal

Octal runs the same tests from Test Drive Speed… in its Activity panel. Open in DriveBench brings the result over, to keep and compare.

Dark mode

Follows your Mac's light or dark appearance, and report images match it.

Signed and up to date

Signed with Apple's Developer ID, notarized by Apple, with auto-updates.

Free to use

DriveBench has no paid tiers or license keys, and nothing is locked. If you find it useful, you can support its development on Ko-fi.

Support on Ko-fi Download