You can set priorities for the foreground synchronization threads and for the merge thread. Adjusting thread priorities can have a significant impact on system performance.
The <Priority> element controls the priority of the foreground synchronization threads. Setting the element's value to zero makes the foreground threads run at their default priority level, which matches that of the mm-sync service when it's started. Nonzero values assign absolute priorities.
Running the foreground threads at a priority level two lower than the default priority level may significantly reduce delays when changing tracks. For example, if mm-sync is running at priority 10, you should set the prioity of the foreground synchronization threads to 8: <Priority>8</Priority>.
The <MergePriorityAdjust> element controls the priority of the merge thread, which is a background synchronization thread that writes entries to the files table. By default, this thread runs at a priority one higher than that of the foreground synchronization threads. For example, if the foreground synchronization threads run at priority 10, the merge thread runs at priority 11.