By default SharePoint is configured to use 3 backup threads.  This can be increased to improve performance and reduce the amount of time taken to backup large farms.  However, the log files can become more difficult to read.

These are the steps required to modify the number of backup threads used by SharePoint:

1. Log in to Central Administration

2. In the Backup and Restore section click Configure Backup Settings

3. Enter a new value for the number of desired threads (between 1-10) and click OK

Modify number of backup threads sharepoint2010