T7 Shield 4TB drives were FAST - Now Extremely SLOW

[cableguy1970]

I have (4) T7 Shield SSD Drives, 4TB size, and all four used to work flawlessly. Now attempting to save data to any of the drives they are going slower than dialup. Over 4 hours to save 4GB. I've used Samsung Magician to ensure all drives have the latest firmware (FXI72P2Q). It's odd that they all are performing exactly the same way. I've used two different Mac computers with the same results: 16" MBP M3 Max, 48 GB Memory and Sequoia 15.4 installed. 2nd Mac is a 16" MBP M2 Max, 96 GB Memory installed. I also have a Samsung T9 SSD, and it's just as slow. Any help would be greatly appreciated.

[Iuser2025]

Hello everyone!

This problem is about a year old, it is actively discussed on many forums, for example on reddit.

Quote from reddit:

I spent three days solving this problem. I have three Samsung T7 Shield SSDs. SSD1, which I use constantly, has no issues. SSD2 is a 4TB with the factory exFAT file system, and SSD3 is a 4TB with two ext4 partitions. Initially, the write speed on SSD2 dropped sharply, and then on SSD3 after two months. I use both SSD2 and SSD3 for backups every 2-3 months.

To fix the very low write speed on SSD:

1) Connect and mount the SSD through a high-performance USB-C port.

2) Write any 500MB file to the disk; at 2MB/s, this will take about five minutes.

3)Leave the SSD untouched for several hours. 

However, if you disconnect the SSD drive, and then connect it after a day or a week, to restore the speed you need again to keep it turned on for several hours.

I really hope that Samsung support service will pay attention to the problem and fix this error.

[JonWood]

There must be something further wrong here.

I've got multiple T5, T7 and one T9 which has developed this problem.

I've tested on multiple computers/ports/cables and no change in performance.

Samsung Magician says the drive is good, but takes alot longer that a T7 to complete the fault test. Still says is read/write speeds are what I had from new, just not achieving it in the real world, to the point of it being unusable.

For a relatively expensive drive that is  only 18 months old, with relatively light use and not even half full, not sure what to do!

Always been happy with the Samsungs in the past, hence me having so many.

[coloradobittersweet]

Oh my!!!!

I thought I posted already tonight, but it is not showing up so I am trying this again.

I had not tried this copy 500MB and then let it sit.  Yesterday I made time to do this.  I pulled out the drive with the most free space.  It showed about 800MB data written to it and 2. 84TB free.  At 3:21:59PM I copied a 1.64 GB file to the T7 Shield and it took 10+ minutes and transferred at about 2MB/s. I then brought up Magician and performed a Performance Benchmark which confirmed the 2 MB/s.  I waited 3 hours and at 6:44:26 PM I copied a different 1.28GB file and it also transferred at 2 MB/s.  I went to bed bummed.

I let it sit. My computer is Windows 11. It does have a power scheme and ultimately goes into a standby mode.  At 7 pm tonight I brought the computer back up.  At 7:05:33 PM I copied a different 1.26GB file and it only took a few seconds :-).  So at 7:08:07 PM I copied a 1.34 GB file and it was about 5 seconds.  Then at 7:13:48 PM I copied another 1.21GB file and again it only took 4-5 seconds.  I brought up Samsung Magician to confirm the speed and ran the exact same test that I have been running which is with Number of Test set to 1 and the Test Range set to 50 MiB, and the performance was 762MB/s and then 803 MB/s.  

Thank you luser2025!!!! This is a start but this is unacceptable.  I hope to contact Samsung directly.  Here is the benchmark screen shot

[coloradobittersweet]

[coloradobittersweet]

Another interesting observation.  Tonight at 7:05 I copied the first 1.26GB file. It is now 8:35 PM and the blue light on the T7 Shield has been blinking with irregular beats from the time I copied and it is still blinking.  It seems to be 4 short flashes and then a longer flash.  I am going just leave this for now, but I don't remember the driving flashing the blue light before like this when I was not copying any data.  

[coloradobittersweet]

More follow-up.  I left that first drive hooked up and the performance was still good after a week.

So, then I pulled out another one of the drives. I verified its performance was still 2 MB/s. 

1) I hooked the drive up, but did not copied data onto it
2) After 2 days the performance was still 2 MB/s
3) I then drag/dropped a 1GB file to the drive.  The Windows copy dialog showed it was transferring at 2 MB/s and would take 6-10 minutes (whatever, I was not looking close and again bummed) so I brought up a different window to do some work in.  However, after some time I noticed it seemed like that copy dialog sped up and all of the sudden it was done.  I didn't think it took 6-10 minutes, so I copied a second >1GB file and sure enough it was transferring it in 3-4 seconds.  

So, this is the second drive that now is fast again, as measured from Samsung it is 833 MB/s.

I really need to set aside time to try to contact Samsung's support team.

[Ercin]

I'm not going to buy this trash. Thanks guys

[coloradobittersweet]

I don't blame you for not wanting to buy it.  It is, thankfully, not actually trash because I still have all my data but definitely not what it should be!

[TomaszHorski]

So I'm not alone! I had T7 Shield 4TB. Read speed 993 MB/s, write speed 2 MB/s. I started RMA and got new T7 Sheld 4TB from Samsung. After 6 months new drive also have 2 MB/s write speed! Tested with 2 cables on 2 computers. So what now? Second RMA? 

[coloradobittersweet]

I know it sounds crazy, but copy a 1GB file onto the drive, and then leave it connected for half a day or so, and retest.  I still have 3 more drives to do this to, but really this is terrible.