The system clock may run fast when you use the ACPI power management timer as a high-resolution counter on Windows 2000-based, Windows XP-based, and Windows Server 2003-based computers

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Article ID: 821893 - View products that this article applies to.
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When a Microsoft Windows 2000-based, Windows XP-based, or Windows Server 2003-based computer runs in Advanced Configuration and Power Interface (ACPI) mode and uses a high-resolution counter, the system clock may run fast.


This issue may occur if the time increment in a program changes and the Hardware Abstraction Layer (HAL) cannot measure the time interval between successive clock interrupts. This causes the system clock to lose a short period of time. When the HAL misses many time-interval measurements in quick succession, the time loss may be significant.

  • This issue may occur on a computer that is running Halaacpi.dll (UP, ACPI, or APIC), Halmacpi.dll (MP, ACPI, or APIC), and Halmps.dll (MP, non-ACPI, or legacy) because these DLLs use the Real Time Clock (RTC) to generate clock interrupts.
  • This issue does not occur on a computer that is running Halacpi.dll (UP, ACPI, or PIC) or Halx86.dll (UP, non-ACPI, or legacy) because these DLLs use the 8254 Programmable Interval Timer (PIT) to generate clock interrupts.


To work around this issue, use one of the following methods:
  • Modify the program to call the timeBeginPeriod function at startup and to call the timeEndPeriod function on exit. This workaround eliminates repeated time increment changes.
  • Modify the program to use the QueryPerformanceCounter() API.


Article ID: 821893 - Last Review: January 7, 2009 - Revision: 5.0
  • Microsoft Windows Server 2003, Standard Edition (32-bit x86)
  • Microsoft Windows Server 2003, Enterprise Edition (32-bit x86)
  • Microsoft Windows XP Home Edition
  • Microsoft Windows XP Professional
  • Microsoft Windows 2000 Server
  • Microsoft Windows 2000 Advanced Server
  • Microsoft Windows 2000 Professional Edition
kbnofix kbprb KB821893

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