2> Loop of Array List until it ends
a> Connect to Content Manager (using CMBConnection, CMBSearchResults, CMBDataManagement) to get the documents belong to the account.
b> If found, create folder in F: drive and copy all documents related to that account to that folder (name same as Account No).
Since all of those process are file creation related operations,
Search tasks maybe negligible if binary search algorithm used(sorted already),
Maybe you can divide the task(the quoted above) and created some threads that will do the divided task and run them concurrently....
That would save more time....