Lightroom Import change copy mode from multithreaded to single threaded

[roy26]

Hi,

I noticed that lightroom copies multiple files in parallel during import which slows down the import process to my external media library QNAP TR-004 (4x 8TB HDD RAID5) dramatically (speed is 25MB/s).

According to robocopy results, the device performs better if the files are copied one by one (single-threaded 120MB/s, multi-threaded equals lightroom import speed of about 25 MB/s).

Is there an option in lightroom that allows to change the copy mode?

OS: Windows 10/11

Lightroom Classic 12.3

Thanks in advance!

[johnrellis]

This is no option to control the concurrent copying of files during import. 

To verify that LR's concurrent copying is indeed the culprit, you could try this experiment, restricting LR to one processor by starting it with this command:

start "Lightroom" /affinity 1 "c:\Program Files\Adobe\Adobe Lightroom Classic\Lightroom.exe"

However, the problem may be caused (or exacerbated) by the parallel preview generation that occurs concurrently with copying files. To rule that out, as an experiment set these options:

1. Off: Preferences > General > Replace Embedded Previews With Standard Previews During Idle Time

2. Off: Preferences > Performance > Generate Previews In Parallel

3. In the Import window, set File Handling > Build Previews > Minimal.