difference in file tranfer speed due to difference in file features?

I'm using Try Ubuntu on a USB drive to use Ubuntu 22.04.4 LTS.This way I'm copying files from an external disc in Ext4 file system to an internal disc in NTFS file system.

I have two folders (folder1 and folder2) with around 800000 files each. Files in folder2 are created from files in folder1. 'file' gives 'ASCII text' as output in both cases. Files in folder1 contain only 5 columns of numbers. Files in folder2 contain a 4-line header and 9 columns of numbers.

Using rsync -a with folder1 takes some hours. However, using the same method on folder2 would take several days at a rate of 1-2 files per second.

Why does it happen?Is there a way to transfer files in folder2 faster?

Here you are more details on the files in the different folders from the stat function

• files in folder1

  Size: 138078      Blocks: 280        IO Block: 4096   regular fileDevice: 851h/2129d    Inode: 92254606    Links: 1Access: (0644/-rw-r--r--)  Uid: ( 1000/ UNKNOWN)   Gid: ( 1000/ UNKNOWN)

• files in folder2

  Size: 394398      Blocks: 784        IO Block: 4096   regular fileDevice: 851h/2129d    Inode: 146939637   Links: 1Access: (0644/-rw-r--r--)  Uid: ( 1000/ UNKNOWN)   Gid: ( 1000/ UNKNOWN)

And from ls -l

• files in folder1

  -rw-r--r-- 1 1000 1000 138078

• files in folder2

  -rw-r--r-- 1 1000 1000 394398

Thank you very much!