Sonoma 4.5 and Samsung T7

[maxmaut]

I don't get what's going on, I'm on M2 Pro, 6 inch MBP and my Samsung T7 Shield 4TB has a write speed of 2-4MB/S. Read speeds are also way lwoer than expexted (around 600 mbps).

I was able to update firmware using samsung's horrendous tool, I updated Sonoma, I ran first aid, erased the drive, nothing helps. On my 2018 intel MBP (which I sold) it was almost 1k mbps.

Weird thing is that if I erase it and format it in Mac OS Extended, the speeds are 800+, but in APFS it's 4. Not 400, it's literally 4.

 

[Fishrrman]

I have a couple of t7 shield drives.

I, too, have noticed this slowdown. Also with write speeds.

For testing, I've been using "AJA System Test Lite".

What follows isn't a "solution", but rather, "a work-around".

Close your software test app
Open disk utility
Make sure you go to the view menu and choose "show all devices".
Now, look at the "list on the left".
Locate the lines for the t7 (there probably will be more than one).
then...
Click on "the top line" first, then click "first aid".
Let the procedure run.
and next...
Click on "the next line down" and repeat with "first aid".
Do this to "all the lines" (hardware and logical entries).

Now...
Quit disk utility and re-open your speed testing app.
Try it again NOW.

After doing this, my write speeds jumped from 4MBps to 900MBps.
(2018 Mini running 10.14 "Mojave").
Read speeds were right up there, as well.

NOTE: the problem may come back again, but the above procedure seems to quell it.

If this works for you, please let us know.

 

[maxmaut]

I have a couple of t7 shield drives.

I, too, have noticed this slowdown. Also with write speeds.

For testing, I've been using "AJA System Test Lite".

What follows isn't a "solution", but rather, "a work-around".

Close your software test app
Open disk utility
Make sure you go to the view menu and choose "show all devices".
Now, look at the "list on the left".
Locate the lines for the t7 (there probably will be more than one).
then...
Click on "the top line" first, then click "first aid".
Let the procedure run.
and next...
Click on "the next line down" and repeat with "first aid".
Do this to "all the lines" (hardware and logical entries).

Now...
Quit disk utility and re-open your speed testing app.
Try it again NOW.

After doing this, my write speeds jumped from 4MBps to 900MBps.
(2018 Mini running 10.14 "Mojave").
Read speeds were right up there, as well.

NOTE: the problem may come back again, but the above procedure seems to quell it.

If this works for you, please let us know.

Thanks, In my post I have mentioned that I did run First Aid, on all drives, physical discs, containers and volumes. No bueno.

What helped so far, and I cannot speak about longevity of this, was to make a backup (I know, I know), then erase the drive and re-create it again, BUT if I was just erasing and formatting in APFS it was NOT helping the issue. ONLY when I formatted it as MacOS Extended, and THEN AGAIN in APFS did my speeds go back up to the expected 800 range.

I tried Samsung's tool to erase as well, didn't help, only this particular double erase helped.

Hope someone can google this and find this solution, albeit it's not the best one since you need another drive to back everything up.

 

[Fishrrman]

Try disk utility's first aid AGAIN, just as I described above.

Don't just "run it once" on the drive.
Follow the instructions I posted.

This "fix" works every time for me.