DiskSpeed is a fast, no-nonsense disk benchmark - measure the real read and write speeds of any internal SSD or external USB drive in seconds.
Pick a drive from the sidebar, choose a test size, and hit Run. DiskSpeed writes and reads real data, shows live throughput as it goes, and keeps a history so you can compare drives at a glance.
Highlights
- Sequential read & write - large-block throughput in MB/s, the number that matters for big file transfers and video.
- Random 4K IOPS - random read and write operations per second, the real measure of everyday app and system responsiveness.
- Every drive, one place - internal SSDs and external USB drives auto-detected in the sidebar with capacity and filesystem.
- Live progress - watch throughput update in real time through each phase of the test, no guessing when it's done.
- Choose your test size - 256 MB for a quick check, 1 GB or 4 GB for results that survive drive caching.
- Detailed result charts - click any result to break sequential and random performance out into clear read-vs-write panels.
- Run history - past benchmarks are saved so you can compare drives or track a disk over time, and any run you don't need is one click to remove.
- Leaves nothing behind - the test file is deleted the moment a run ends, even if you quit halfway through.
- Native & light - a tiny native app with light, dark, and auto themes, plus a one-click update check, all in Settings.
How it works
DiskSpeed runs an actual read/write workload against the drive you select - it doesn't estimate from specs, and it skips the system's memory cache so you measure the drive, not your RAM. Sequential passes move large blocks to gauge raw bandwidth, while the random 4K pass fires many small operations to measure IOPS. A bigger test size reduces the effect of on-drive caching, so choose 1 GB or 4 GB when you want the most honest numbers.
Perfect for
- Buying a drive - confirm a new SSD or USB stick actually hits its advertised speed.
- Creators & editors - check that your scratch disk keeps up with 4K video workflows.
- Spotting a slow disk - catch a failing or throttled drive before it costs you a deadline.
- Comparing drives - benchmark several drives and let the saved history settle the argument.
