filecopy.num_workers (collection.cfg setting)
This option is the maximum number of worker threads that will run during an update of a filecopy collection. These threads will perform any operation that does not involve interacting with the fileshare e.g. filtering & storing files etc.
This could be usefully increased if you have multiple cores on your gathering machine.
This value can be overridden by the gather.slowdown.threads setting if a slowdown period has been specified.