For large record sets, select the Bulk API option as it processes results in a fraction of the time while using less API calls than the traditional SOAP API. Bulk API is based on REST principles and is optimized for working with large sets of data. You can use it to insert, update, upsert, dedupe, or delete large record sets asynchronously using parallel processing.
*Not available with Salesforce Professional Edition
The Bulk API option is available in Import, Export, Delete, Dedupe, and Verify.