AmorphousDiskMark
CrystalDiskMark’s test suite on macOS — sequential and random read/write in MB/s and IOPS.
What it does
AmorphousDiskMark measures storage performance with the same test shapes CrystalDiskMark made standard: sequential 1 MiB reads and writes at various queue depths, and random 4 KiB operations, reported in both MB/s and IOPS.
That matters because sequential and random performance are unrelated numbers. A drive advertising 1,000 MB/s sequential may be dismal at 4 KiB random, which is the figure that determines whether a VM or a database on it feels fast.
Notes
Use it to check what an enclosure and cable combination actually deliver — a Thunderbolt SSD negotiated down to USB 2.0 is immediately obvious in the numbers, and WhatCable explains why. Free on the App Store, with in-app purchases for extra test profiles.
Alternative to
| Alternative | Type | Trade-off |
|---|---|---|
| Blackmagic Disk Speed Test | Free | App Store, sequential throughput only |
| fio | Open source | The serious tool, fully scriptable, no interface |
dd | Built in | A crude sequential number in one command |
Install
AmorphousDiskMark on the Mac App Store
Or with mas:
mas install 1168254295