New 2TB portable hard drive has ~2MB/s read and write speeds

Question

I bought a Seagate Expansion Portable 2TB (current version) recently.

I've begun writing some data to it, and it's about 5% full now. But, the write speed was getting awful. At first, I thought this was due to SMR, but after learning more about SMR, I think that it shouldn't affect read speeds, and write speeds should only be affected after writing dozens of GB continuously, and should recover after idling for <10 minutes.

This drive has been idling for hours, and I currently get around 2MB/s reads and writes.

Every diagnostic, including Seatools from Seagate, and SMART, passes it with no issues.

The performance problem happens both on Windows and Linux, on different machines, and on different USB ports on each machine (both USB 3 and 2).

It certainly looks like it's a faulty drive, but I don't understand why no diagnostic, including Seagate's own, pick up any issues. Surely 2MB/s reads is an issue?

For some reasons on the below invocation of CrystalDiskMark the write speeds are zero, but usually they were around 2MB/s to 6MB/s.

------------------------------------------------------------------------------
CrystalDiskMark 7.0.0 x64 (C) 2007-2019 hiyohiyo
                                  Crystal Dew World: https://crystalmark.info/
------------------------------------------------------------------------------
* MB/s = 1,000,000 bytes/s [SATA/600 = 600,000,000 bytes/s]
* KB = 1000 bytes, KiB = 1024 bytes

[Read]
Sequential 1MiB (Q=  8, T= 1):     2.096 MB/s [      2.0 IOPS] <2529502.09 us>
Sequential 1MiB (Q=  1, T= 1):     1.046 MB/s [      1.0 IOPS] <868586.28 us>
    Random 4KiB (Q= 32, T=16):     0.002 MB/s [      0.5 IOPS] < 19650.23 us>
    Random 4KiB (Q=  1, T= 1):     0.125 MB/s [     30.5 IOPS] < 32266.59 us>

[Write]
Sequential 1MiB (Q=  8, T= 1):     0.000 MB/s [      0.0 IOPS] <    -1.00 us>
Sequential 1MiB (Q=  1, T= 1):     0.000 MB/s [      0.0 IOPS] <    -1.00 us>
    Random 4KiB (Q= 32, T=16):     0.000 MB/s [      0.0 IOPS] <    -1.00 us>
    Random 4KiB (Q=  1, T= 1):     0.000 MB/s [      0.0 IOPS] <    -1.00 us>

Profile: Default
   Test: 128 MiB (x1) [Interval: 0 sec] <DefaultAffinity=DISABLED>
   Date: 2021/06/07 14:17:46
     OS: Windows 10 Enterprise [10.0 Build 19042] (x64)

Answer 1

So, the problem has gone away after doing a quick format in Windows 10. Performance has jumped up to around 105MB/s reads and writes, and it's sustained even after copying hundreds of GB.

I don't have any explanation why doing this should have altered the read and write speed of the drive. It was a brand new drive. And, many of the ways I had tested read/write speed were accessing the raw drive and bypassing the formatting anyway (eg, dd).

But since it's appropriate to give the solution I found for myself, here is my answer, such as it is.