DLO is happening to cause slowness on clients.

We use DLO  7.6  to backup clients data and pst file.i have created a profile and set it backup whenever a file changes and use delta file transfer for pst.

When DLO start to sync with pst file CPU usages seems % 25 and disk usage % 100 on all clients. Even i have tried to incremental backup and VSS backup for PST but nothing has changed so during sync clients cant work with their computers.

How can i solve it ?