Windows 10: Recent drop in File Copy Performance

I'm experiencing much slower speeds when copying files to one of my PCs. I've done a bunch of tests to narrow down the issue, but I have no idea how to fix it now that I've narrowed it down.


So I have two Windows 10 PCs, one with two USB3 raid5 devices attached to it for backup purposes, and a gigabit network connecting them. For ease of discussion I'll call them SOURCEPC and BACKUPPC. I regularly (every 2-4 weeks?) dump a large amount of video files from SOURCEPC to BACKUPPC - but today it's suddenly taking a huge dive in speed after transferring a couple large files.


This new speed issue only applies to one of the two external raids, so I'm not sure if it's a Windows Update that's screwed up the way the files are handled, or if it's an indication that one or more drives in the problem raid are going bad? They're by the same manufacturer but I think they use different drivers, so even though the issue only happens with one I can't be sure it's a sudden hardware issue. And the "bad" raid doesn't show any error lights or messages.


I've narrowed the problem down to the way Windows handles the file transfer - if I look at the Resource Monitor I can see Windows ("SYSTEM" PID 4) is still writing to multiple files for a significant amount of time after SOURCEPC has finished sending them. So over time they build up and once Windows is writing 5-10 files at once the RAID starts choking and the network speed drops from 70-120MB/s down to 5MB/s, making what should be a 10GB, 2-3 minute transfer take like 30 minutes.


So my second question, are these files actually done transferring within a second or two of when SOURCEPC thinks they're finished, or are they only done once Resource Monitor shows there's no data transferring to the files? Because on the "good" raid it kept writing data to 4 files for 30-60 seconds at about 13MB/s each (585MB out of 10GB?), and on the "bad" raid it kept writing about 7MB/s shared among a bunch of files for a whole 10 minutes (or roughly 4200MB out of 10GB)


Both of those numbers seem absurd to me, I knew transfers weren't instantly complete for USB drives, but even 30 seconds of data seems like a hell of a lot to be cached on BACKUPPC while telling SOURCEPC that the transfer is complete. Both USB drives are set to "Better Performance", not "Quick Removal".


The "bad" raid also has an additional section which the other doesn't have, "Write-caching policy". This has "Enable write caching on the device" turned on, and "Turn off Windows write-cache buffer flushing on the device" turned off.


Any suggestions would be appreciated. I also tried disabling Microsoft Security Essentials, SysMain (previously called Superfetch), and Indexing, and reverting the Windows Update - none of those had any impact on the issue.


I also did a quick test from an internal hard drive to each of the USB raid boxes and the "good" one writes the entire amount at 50-200MB/s - the "bad" one starts writing at 100-200MB/s but quickly chokes after the 1-2GB transfers.

:)

 

Recent File List

Remove-ItemProperty -Path "Registry::HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion
\Applets\Paint\Recent File List" -name file1

Remove-ItemProperty -Path "Registry::HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion
\Applets\Paint\Recent File List" -name file2
Remove-ItemProperty -Path "Registry::HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion
\Applets\Paint\Recent File List" -name file3
Remove-ItemProperty -Path "Registry::HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion
\Applets\Paint\Recent File List" -name file4
Remove-ItemProperty -Path "Registry::HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion
\Applets\Paint\Recent File List" -name file5
Remove-ItemProperty -Path "Registry::HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion
\Applets\Paint\Recent File List" -name file6
Remove-ItemProperty -Path "Registry::HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion
\Applets\Paint\Recent File List" -name file7
Remove-ItemProperty -Path "Registry::HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion
\Applets\Paint\Recent File List" -name file8
Remove-ItemProperty -Path "Registry::HKEY_CURRENT_USER\SOFTWARE\Microsoft\Windows\CurrentVersion
\Applets\Paint\Recent File List" -name file9
...

you get the idea. ( too lazy to put it in a for loop and test it.

or just open regedit and remove all the fileX from that key.

 

Java.nio.file - Copying files

You can't copy a folder, thats why it generates an exception (you are trying to copy a folder using a copy file function).
You probably need to list all the files inside that folder and copy one by one

 

Java.nio.file - Copying files

Issue was the above, so thanks temp02.