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LabWindows/CVI Timer Functions Run Improperly on AMD Athlon 64 X2 Systems

Primary Software: LabWindows/CVI Development Systems>>Base Package
Primary Software Version: 8.0
Primary Software Fixed Version: N/A
Secondary Software: LabWindows/CVI Development Systems>>Full Development System

Problem:
My timer functions run improperly on PCs with AMD-Athlon 64 X2 Processors, but seem to work on other systems. Why am I seeing this behavior?

Solution:
The CVI timer functions use the Windows QueryPerformanceCounter() function, which is known by Microsoft to have problems in x64-based versions of Windows. Specifically, systems with computers running an x64-based version of Windows and with AMD Cool‘n’Quiet technology enabled are affected.

The problem can usually be solved by either updating your BIOS, or by modifying your boot.ini file to use the /usepmtimer switch. Information on these items can be found in the Microsoft KnowledgeBase linked below.

Related Links:
Microsoft KnowledgeBase [895980]: Programs that use the QueryPerformanceCounter() function may perform poorly in x64-based versions of Windows

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Report Date: 02/13/2006
Last Updated: 03/08/2006
Document ID: 3UC8EDHY

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