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.