Microsoft : Investigating Slow copy of big files

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https://support.microsoft.com/en-us/topic/september-30-2022-kb5017389-os-build-22621-608-preview-62f353a0-696a-49d8-a78f-a14910f30ae3#knownissues

Copying large multiple gigabyte (GB) files might take longer than expected to finish on Windows 11, version 22H2. You are more likely to experience this issue copying files to Windows 11, version 22H2 from a network share via Server Message Block (SMB) but local file copy might also be affected. Windows devices used by consumers in their home or small offices are not likely to be affected by this issue.

To mitigate this issue, you can use file copy tools that do not use cache manager (buffered I/O). This can be done by using the built-in command-line tools listed below:

robocopy \\someserver\someshare c:\somefolder somefile.img /J

or

xcopy \\someserver\someshare c:\somefolder /J

We are working on a resolution and will provide an update in an upcoming release.

Ned Pyle Microsoft
I can’t share too many details yet, but we know exactly where it is getting slower in Kernel, nothing to do with SMB or compression.

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Why you stay away from new feature releases.

Susan Bradley Patch Lady

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dearnold, JohnW

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recently from Bleeping Computer – Microsoft fixes Windows 11 22H2 file copy performance hit

https://www.bleepingcomputer.com/news/microsoft/microsoft-fixes-windows-11-22h2-file-copy-performance-hit/

and from this MS Community forum thread:
https://techcommunity.microsoft.com/t5/storage-at-microsoft/slower-smb-read-performance-for-large-files-in-22h2/bc-p/3644556

Fix update 11/28/2022: The preview fix for this issue is now available in Windows 11 Insider Preview Build 25252. The final fix for Windows 11 22H2 production computer will come in a normal monthly Cumulative Update through Windows Update once validated in Insider builds.

so this problem will soon get a bug fix in an upcoming 22H2 cumulative update

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fix for slow copying problem in 22H2 included in the Jan. 5, 2023 beta insider builds 2262x.1095 (KB5022364):
https://blogs.windows.com/windows-insider/2023/01/05/announcing-windows-11-insider-preview-build-22621-1095-and-22623-1095/

We fixed an issue that affected how fast you could copy items from a network to a local computer. For some users, the copy speed was slower than expected.

gonna wait and see if such bugfix will make it onto the January 2023 patch Tuesday update (1/10) for non-insiders

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dearnold

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