Microsoft KB Archive/873289

= Task Manager may not calculate CPU usage correctly on Windows 2000, Windows Server 2003, or Windows XP =

Article ID: 873289

Article Last Modified on 10/30/2006

-

APPLIES TO


 * Microsoft Windows Server 2003, Standard Edition (32-bit x86)
 * Microsoft Windows Server 2003, Web Edition
 * Microsoft Windows Server 2003, Enterprise Edition (32-bit x86)
 * Microsoft Windows XP Professional
 * Microsoft Windows 2000 Advanced Server
 * Microsoft Windows 2000 Server
 * Microsoft Windows 2000 Professional Edition

-





SYMPTOMS
When you view the Processes tab in Task Manager, you notice that the sum of the CPU value for the System Idle Process object and the CPU Usage value that is reported in the status bar may be more than 100 percent. Sometimes the sum may be more than 140 percent.

Note The System Idle Process indicates the unused percentage of the CPU.



CAUSE
This issue occurs because Task Manager does not associate deferred procedure calls (DPCs) or interrupts with the processes that request them. This can cause CPU Usage and System Idle Process calculations that are not correct.



WORKAROUND
To monitor CPU performance more accurately, use System Monitor. To do this, follow these steps:
 * 1) Click Start, click Run, type perfmon, and then click OK.
 * 2) In Performance, click the New Counter Set button in the details pane.

Note Move the pointer over the buttons in the details pane to find the New Counter Set button.
 * 1) Click the Add button.
 * 2) In Select counters from list, click %Processor Time, and then click Add.
 * 3) In Select counters from list, click %Idle Time, and then click Add.
 * 4) Click Close.
 * 5) Click the View Report button.

