Understanding the System Stability Index

Applies To: Windows Server 2008, Windows Vista

Based on data collected over the lifetime of the system, each date in the System Stability Chart includes a graph point showing that day's System Stability Index rating. The System Stability Index is a number from 1 (least stable) to 10 (most stable) and is a weighted measurement derived from the number of specified failures seen over a rolling historical period. Reliability Events in the System Stability Report describe the specific failures. For more information about interpreting the System Stability report, see Use Reliability Monitor to Troubleshoot.

  • Recent failures are weighted more heavily than past failures, allowing an improvement over time to be reflected in an ascending System Stability Index once a reliability issue has been resolved.

  • Days when the system is powered off or in a sleep state are not used when calculating the System Stability Index.

  • If there is not enough data to calculate a steady System Stability Index, the graphed line will be dotted. When enough data has been recorded to generate a steady System Stability Index, the graphed line will be solid.

  • If there are any significant changes to the system time, an Information icon will appear on the graph for each day on which the system time was adjusted.

Additional references