Windows 10 V1903: Is there a speed drop during file copy?

[German]Windows 10 version 1903 might have a problem copying files. The disc load could reach 100%, causing the copy speed to slump. Here is some information about what I know about it so far.


Blog-reader Ismael D. has brought this possible problem in Windows 10 Version 1903 to my attention (thanks for that). So I'll post it in the blog for information.

Speed drop when copying files

It is possible that Windows 10 version 1903 may lose speed when copying files after 10 seconds. The effect is discussed in this forum post

Mass file copy speed starts fast but slows down, then fast again

My laptop had an M2 SSD and a SATA HDD. I bought a SATA SSD to replace the SSD. I copied everything from the HDD to an external USB drive, then physically replaced the HDD with the new SSD and formatted it using Manage-> Disk Management.

When I copied the files I had backed up to the external USB drive back to the new SSD drive, the file copy stared off fine, but then unexpectedly slowed down after a few tens of seconds. After running at the slow speed for about a minute, it sped up again to full speed. This cycle repeated until the file transfer was finished.

At first I thought it was the USB HDD, but then I tried with the M2 SSD. This is blazingly fast, so the problem occurs after a significant amount of data has been transferred, but it is there. Initially, the disk usage is low and the transfer speed fast, limited by the slowest disk/ interface. Then suddenly the disk usage on the internal destination disk will go to 100%, regardless of which drive it is. This causes the transfer speed to slow down to about 10 MB/s. After a while, the disk usage automatically drops to a low value and the transfer speed goes back to the previous fast speed.
Speeds switch between two values: (ignoring the initial burst of cached speed).

USB drive to SATA SSD: ~110 MB/s and ~10 MB/s (USB drive is HDD, so 110MB/s is good)
M2 SSD to SATA SSD: ~500 MB/s and ~10MB/s
USB drive to M2 SSD: ~110 MB/s and ~10 MB/s
SATA SSD to M2 SSD: ~500 MB/s and ~10MB/s
The new SSD in question is a Pioneer 1 TB 2.5" (APS-SL3N-1T).

According to the report above, the copy speed will be reduced to ~10MB. After some time the process will recover and the old speed will be reached again. The effect occurs both on an HDD and on the M2 SSD drive. Question: Have any of you observed this behavior before?

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7 Responses to Windows 10 V1903: Is there a speed drop during file copy?

  1. Lucas says:

    Yes, same problem here, and I have no ideia how to fix it.

    • Terrell Griffin says:

      Just another reason to hate Win10. It seems they have enough issues and this one has existed for some time with no found resolve.

  2. Derek says:

    I am having this issue as I type. Transferring just under 1TB and it's already been 7h 49m with 20% to go. The target drive is pinned at 100%.

  3. Hale says:

    the same and on every windows 10
    Microsoft just denies and ignores, ofering to look for the problem in your hands.
    Another reason to stay with Windows 7 even while the support has ended… having a good 3rd party firewall and antivirus is better than having tons of unsolvable system problems.

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  5. The Cuong says:

    I have the same issue and it is really annoying.
    It is even worse with my laptop since all USB ports and external hard drives are still good but the speed of transferring dropped down to 0~300kb/s.
    I have tried many methods but can not solve.

  6. Jj says:

    I have same problem.
    Recently; 1 month after installing my "TM4PS7256G0C101" m.2 SSD, while copying jsut "one" 1GB file, like movie or zip file, the speed is about 10MB/s . while before, it's speed was about 50MB/s to 128MB/s with the same file.
    And my laptop freezes recently then encounters with Blue Screen of Death. I think because of the SSD.

  7. John says:

    Same problem with the newest updates in November 2020, brand new computer, copying several TB from an external hard drive. the speed varies between 0 KB/s to 124 KB/s but mostly less than 50. Estimated time has gone from 5 hours to over 24 and back to 5.

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