Mac app · Support
Disk & Cable Speed
Measures your drive's real write and read speed, then tells you in plain words whether the cable, a hub or the drive itself is slowing it down. Free on the Mac App Store.
Why does it ask for permission to use my drive?
The test writes a temporary file on the drive and reads it back. macOS only lets an App Store app write to an external drive you choose, so the app asks once and remembers. The file is deleted after every test.
It says my cable is holding the drive back. What do I do?
Your drive supports USB 3 but connected at USB 2.0 speed. Use a USB-C cable rated 10 Gb/s, plug it straight into a port on the Mac rather than a hub, dock or monitor, and press Start again. The app notices the new cable on its own.
Why is my read speed higher than my write speed?
That is normal for most SSDs and hard drives. Writing is the harder job, especially once a drive's fast cache fills up during larger tests.
Does it work with internal drives and Thunderbolt?
Yes. Pick any drive from the menu at the top right. The built-in drive is tested without any permission prompt.
Contact
Questions, bugs or ideas: email me and include your Mac model and the drive you tested.
joshuabascos@gmail.comPrivacy
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