In article , MC
wrote:

It sounds like PS is suffering from some kind of bottle neck with
regards the amount of automation it is trying to handle. Now this
could be a weakness in PS itself, unable to process so many images at
once, but I would rather believe that it is down to disk/scratch disk
access speed rather than space on the disk itself. It could even be a
memory size/speed bottle neck. PS wants to do things as fast as it is
capable but if the hardware is stalling then PS will stall also, and
will top and complain about it.

that is highly unlikely. photoshop manages its own memory and scratch
space to avoid bottlenecks imposed by the operating system.

Have you tried smaller batches to see how PS handles them.

that's not the issue.