Using the Separate Archives button (ARCHIVE=single) to archive multiple folders separately seems to act differently from creating a single archive - performance wise.
For some reason it is reading then writing to the same zip for every new file added to it over and over it seems. As shown in the screenshot. But nothing like that happens when creating just a single zip. Then the hdd is not stressing and is done is seconds even though there are thousands of files, but seems like it would take an hour using the separate archives button.
The option Use temporary file when copying to Zip files along with the one for removable drives are both disabled, but maybe has something to do with it?
Okay, not to be rude i'm not a developer but. If a script can fix this why not change the ARCHIVE=single internal programming to fix this for everyone?
I could spend an hour explaining the internals but it wouldn’t really help either of us. The reason it’s still the way it is is the usual one: It’s not a trivial change and other work has taken priority so far.
It would be good to change it to always use batch mode when we have the bandwidth to spare, but until then there is a good workaround in the form of the script I posted.