How best to test read/write speeds of USB-drives

[DominikHoffmann]

I am wondering about how to reliably test the read and write speeds of volumes attached to my Mac.

I installed Blackmagic Disk Speed Test, but it fails when testing a brand-new Kingston Kyson flash drive. So, now I am wondering about alternative utilities that can do this. The Blackmagic utility’s features are fine, but this

doesn’t make sense. Prior to that, write speed (16-in M1 MacBook Pro, through an USB-C-to-USB-A adapter) was reported to be 28.2 MB/s. The part is rated at 60 MB/s write speed. I have never tested read/write performance before, so I don’t know, what’s reasonable, at all, which is why I am looking for an alternative utility for a second opinion. I do know that that error is not supposed to happen.

 

[rpmurray]

Try downloading AmorphousDiskMark from the Mac App Store.

 

[DominikHoffmann]

Try downloading AmorphousDiskMark from the Mac App Store.

Thanks! That’s more like it. Still, with that write speed is reported to be only around 16 MB/s. Read speed is at the specified 200 MB/s.

 

[MarkC426]

Sounds like a 'low quality' drive.
Connected to USB-A drive will be slower than USB-C.

My Samsung T7 (USB-C) reports about 700-800MB/s in Blackmagic test.

 

[Alpha Centauri]

Thanks! That’s more like it. Still, with that write speed is reported to be only around 16 MB/s. Read speed is at the specified 200 MB/s.

What capacity is the drive? On their own site they advertise 200MB/s read, 60 MB/s write for 128GB/256GB. The 32GB/64GB is rated at 200MB/s read but write speeds aren't on the specs sheet at all.

Edit: my Samsung duo plus 256GB USB-C/A writes over 100 Mb/s. It's quite noticeable.

 

[gilby101]

What capacity is the drive? On their own site they advertise 200MB/s read, 60 MB/s write for 128GB/256GB. The 32GB/64GB is rated at 200MB/s write but read speeds aren't on the specs sheet at all.

My reading of the web page https://www.kingston.com/en/usb-flash-drives/datatraveler-kyson-high-performance-usb-flash-drive is that the 32/64GB ones a rated as up to 200 MB/s read with no rating for write speed.

Still, with that write speed is reported to be only around 16 MB/s

How is the drive formatted? To be honest I am not surprised by your experience. Flash Drives are mostly for storing a bit of data, not for anything that requires higher performance.

Given that performance is presumably an issue for your usage, I suggest (from Kingston) https://www.kingston.com/en/usb-flash-drives/datatraveler-max

 

[DominikHoffmann]

I landed on this topic, because I found a SD card in my SD card reader and wanted to know, whether I could run my Mac off it, because it has a capacity of 128 GB. I had never run those tests before and wanted to benchmark the SD card against my flash drives, which I mainly use for booting into macOS installers. I have them for Snow Leopard, Lion, etc., all the way to Ventura. Only the later ones use USB-3 flash drives, which makes a huge performance difference. It does turn out that the SD card is faster than the flash drives, but possibly not well suited for holding a bevy of very small files as would be the case with an OS installer.

 

[gilby101]

I landed on this topic, because I found a SD card in my SD card reader and wanted to know, whether I could run my Mac off it, because it has a capacity of 128 GB.

As well as write performance limitations, many SD cards have a limited TBW (TeraBytes Written) over their lifetime. This makes them unsuitable for a complex (highly active) operating system like macOS. TBW is at least as important as write MB/s when assessing SD cards (and USB thumb drives).

I have kept macOS on USB thumb drives, but only as disaster recovery media for short term use.

 

[Alpha Centauri]

My reading of the web page https://www.kingston.com/en/usb-flash-drives/datatraveler-kyson-high-performance-usb-flash-drive is that the 32/64GB ones a rated as up to 200 MB/s read with no rating for write speed.

Indeed what I meant but wrote back to front. Thanks for the correction, have just edited it.