Working with backup sets : VSS-aware backup sets (Windows) : Restoring a VSS-aware backup set : Specifying performance options
 
Specifying performance options
On the Select restore performance options page, the special performance options are intended for large backup sets in high performance environments.
For typical use, keep DS-Client’s default settings, and then click Next.
More information in F1 help: "Select Restore Performance Options (Windows DS-Client)"