At last I thrashed away those good ol' st380011a I used for years in order to maintain multiple back ups for my docs, I replaced them by cheapo kingston usb flash drives.

I've bought total four because I use three but one apparently died.

Now two of them run kinda good velocities but the other one seems more slow.

Can I get a program that will print me read and write benchmarks for the drives? I need that it would do its thing using only the available space.

Using Terminal and Homebrew if necessary wouldn't be an issue.

Also should I use this ìotop` program while rsyncing in order to verify the possibly different drive speeds?

$ iotop
dtrace: system integrity protection is on, some features will not be available
dtrace: failed to initialize dtrace: DTrace requires additional privileges
  • 2
    I see at least two questions here, which may be one of the reasons you didn't get answers. Also, what kind of research on this have you done yourself and why don't the solutions you've found meet your requirements?
    – nohillside
    Commented Sep 15, 2020 at 13:13
  • A popular app to benchmark drives on a Mac is Blackmagic Disk Speed Test. Why did you not go for the first Google result?
    – n1000
    Commented Sep 16, 2020 at 7:00
  • 1
    Use dd. dd if=/dev/zero of=/volume/<USB name>/<tmp name> and ctrl+c after a few seconds. dd will give you an average speed.
    – Joy Jin
    Commented Sep 20, 2020 at 3:36
  • Or, if your drive is slower than 10MB/s, use dd if=/dev/random of=/volume/<USB name>/<tmp name> to test the real speed in case the drive uses some kind of compression.
    – Joy Jin
    Commented Sep 20, 2020 at 3:37

1 Answer 1


You will find that "cheap usb flash drives" are not a long term solution for backup. Many will die sooner than you wish, and most will be slower than you like.

I googled "mac drive test utility" and found a number of good test utilities. "Blackmagic Disk Speed Test" is free. It will test USB memory sticks. Also regular drives, and ssd drives. I tested one of my memory sticks and it said 15.7 MB/s write, 21.3 MB/s read. The test does not disturb any pre-existing data.

As far as I can tell, speed is the only thing tested by "Blackmagic Disk Speed Test". Hence the name? Longevity is not really testable, and was not mentioned in the original question.

I can also recommend DriveDx by https://binaryfruit.com. You can use a trial version free for a while, but it is only $20 for a license. It promises to test "remaining life" which is pretty close to longevity.

  • 1
    Telling people to google for tools isn't the best way to answer a question, it requires additional steps from people to find the actual answer. If "Blackmagic Disk Speed Test" is an answer, why not include a link to it (and maybe a summary of what it does) directly in your answer?
    – nohillside
    Commented Sep 17, 2020 at 8:26
  • Especially how it tests the longevity of the usB stick
    – mmmmmm
    Commented Sep 17, 2020 at 10:51
  • my workflow includes several stick mirrors and full drive hashing from time to time - guess what actually those sticks lose sectors slower than rotating devices
    – 146438
    Commented Sep 18, 2020 at 21:42

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