I would to test the relative performance of various external storage devices:

  • Thumb drive
    • Samsung MUF-256AB/AM FIT Plus 256GB - 300MB/s USB 3.1 Flash Drive (256 gigs)
  • Spinning metal drive
    • Toshiba Canvio Advance 1TB Portable External Hard Drive USB 3.0, Blue (HDTC910XL3AA)
  • NVMe M.2 solid-state storage adapter
    • EXMTE M.2 NVME USB 3.1 Adapter M-Key M.2 NGFF NVME to USB Card High Performance 10 Gbps USB 3.1 Gen 2 Bridge Chip
    • Samsung 970 EVO Plus Series - 250GB PCIe NVMe - M.2 Internal SSD (MZ-V7S250B/AM)

I do not care about free-of-cost or not, I'd be okay with paying a fee.

I understand benchmarking tools are always biased and unrealistic as compared to real-world usage. Nevertheless, I would like to get an objective sense of the reading and writing throughput on these devices. In particular I would like to see if the NMMe M.2 can saturate the USB 3.0 port on my MacBook and the USB 3.1 port on my Mac mini.

Testing on:

  • MacBook Pro (Retina, 15-inch, Late 2013)
  • Mac mini 2018

I found a couple similar Questions (here & here), but they are 7-8 years old. I imagine things may have changed, now in 2019.

  • 3
    Finder and activity monitor can show you iops and data rates fairly specifically. Xcode has instruments if you need even better data. We should close this as duplicate and update the old answers with new results, though. What specific item you wish to benchmark might make this different enough to keep open so if it gets closed, just focus on making this about something more specific than whatever dupe is selected should that happen.
    – bmike
    Jul 1, 2019 at 0:50

2 Answers 2


Blackmagic Disk Speed Test

If you're interested in read and write speeds there is an app called Black Blackmagic Disk Speed Test available on the App Store. This doesn't have a database to compare with others but can give you actual speeds for your internal and external drive.

  • 1
    Yes, that app does the trick, thanks. It does a simple test of repeatedly writing then reading a 5-gig file. In the "gear" icon, choose a disk to target. Press the Start button to start, watch the gauges go, and press Start again to halt. If curious, my approximate results on a USB 3.0 port with a theoretical limit of 5 gigs per second: (A) Internal memory is around 900 megs/second (0.9 gigs) (B) The 970 EVO Plus in in a USB 3.0 adapter and in a USB 3.1 adapter got the same > 400 megs/s in both adapters (C) Spinning disk around 100 MB/s (D) thumb drive around 65 MB/s writes and 300 MB/s reads. Jul 1, 2019 at 6:15

AJA System Test is another commonly used tool to benchmark disk performance for the Mac. It offers graphs and a text report of performance instead of just a dial indicating transfer speed like Black Magic.

If you want to test random I/O, which neither AJA or Black Magic do, you can use the tool fio like you can on Linux. You can expect the IOPS to be much higher on an SSD than on a HDD in this case. fio is available from Homebrew

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