Why does copying 60,000 small files from an SSD through USB 2.0 to a 3.0 USB have a throughput of 25kB/s-75kB/s?

I have done some rough rounding above, and took the time to write more accurate numbers.

The actual total is 49,436 items, totalling 244.9 MB. Copying all of this was going to take at least an hour.

And another copy was 8,082 items, totalling 76.0 MB, 8,081 items, totalling 72.6 MB, 13,825 items, totalling 9.1 MB, 13,825 items, totalling 9.1 MB, 2,068 items, totalling 29.0 MB, 3,555 items, totalling 49.1 MB. Copying these separately, yet concurrently took minutes.

Both of these were from the same SSD to the same usb stick.

Regarding the large files

4,127 items, totalling 43.1 GB took more than 8 hours

Another non-concurrent batch copy of 73 items, totalling 725.5 MB, 163 items, totalling 1.4 GB, 1,332 items, totalling 13.0 GB, 721 items, totalling 8.9 GB, 507 items, totalling 7.1 GB, 27 items, totalling 476.6 MB, 17 items, totalling 456.7 MB, 15 items, totalling 409.1 MB, and 1,272 items, totalling 10.6 GB took under an hour.

But actually, that was hard drive to sd card vs usb to hard drive respectively. I stopped the single copy operation containing all from usb to hard drive because it was estimating too long and I remembered the trick using the small files.

totalling: spelling error in Files.

Your numbers are not representative because we explained you that you copy over 3 different File systems.
We gave you several alternatives to test, and for me it looks like you insist to do it the way you do it since beginning.

About your argument of being a problem of the Kernel is not valid, your article is also almost 10 Years old. Fat32 and NTFS are proprietary file systems and will not be integrated in the Linux Kernel. EXFat on the other hand is open and is integrated in the newest Kernel. Did tyou try with ExFat? Did you try Rsync? Did you make a Zip-File ?

It is quite normal that on the proprietary OS things are faster as there you work with native file systems.

I beg the @admins to close the topic as the discussion is already made.