Description

Editor's Review

By Sarah Johnson, Senior Security Analyst

CrystalDiskMark is an open-source software developed by Japanese developers to test the read and write speeds of hard drives. It supports a variety of storage devices including HDDs (mechanical hard drives), SSDs (solid state drives), and USB drives.

CrystalDiskMark is the de-facto standard for quick, repeatable storage benchmarks. In less than 60 seconds it measures sequential and random performance with real-world block sizes—information you need when you buy, tune or troubleshoot SSDs, HDDs, USB sticks, SD cards or RAID arrays.

What it tests

SEQ1M Q8T1 – large sequential transfers (think movies, ISOs, backups).
SEQ128K Q32T1 – typical consumer queue depth.
RND4K Q32T1 – high-queue random (database, VM, content-creation).
RND4K Q1T1 – low-queue random (OS boot, everyday apps).

Results are shown in MB/s and IOPS; higher is better, but watch the queue-depth line—cheap drives look good at Q32 yet crawl at Q1.

Why the 4 K score matters

Windows, games and Office spend most of their time opening 1-128 KB files. A SATA SSD that hits 500 MB/s sequential but only 10 MB/s 4 K Q1 feels slower than a 3 000 MB/s NVMe drive that also manages 70 MB/s 4 K Q1. CrystalDiskMark exposes that gap in one screen.

Quick start guide

Extract the ZIP—no installer needed (portable edition available).
Run DiskMark64.exe (or DiskMark32.exe on older PCs).
Select target drive, test size (1 GB is default), number of passes (3-5 gives stable averages).
Click All or choose a single test; wait ~30-60 s.
Press File → Copy to grab plain-text or PNG for forums / tickets.

Typical USB thumb-drive reference

Interface	Sequential Read	Sequential Write	RND4K Q1 Read
USB 2.0	35 MB/s	10 MB/s	2 MB/s
USB 3.2 Gen 1	150-200 MB/s	30-80 MB/s	5-15 MB/s
USB 3.2 Gen 2 NVMe enclosure	1 000 MB/s	900 MB/s	50 MB/s

Pro tips

Disable write-cache in Device Manager before testing if you want worst-case numbers.
Leave 10 % free space on SSDs; a full drive can drop 4 K write by 70 %.
Use -c command-line switch for unattended scripts: DiskMark64.exe -c 5 -d D -o result.txt.
Compare the same test size (e.g. 1 GB) when reviewing drives—small 50 MB tests fit in SLC cache and inflate scores.

Bottom line

CrystalDiskMark is small, free and vendor-neutral. If a storage device can’t post decent 4 K Q1 numbers here, it won’t feel snappy in real life—keep the benchmark handy before you buy or RMA.