Using the TestStand Seconds Function or Wait Step May Result in Incorrect Elapsed Time

Issue Details

When using TestStand Seconds(True) or Wait steps, the elapsed time may appear incorrect:

• Seconds(True) returns a value that increases slower than actual time.
• Wait steps take 1.5x–2x longer than specified.

This issue occurs only on some machines; others behave as expected. Both Wait steps and Seconds(True) call the Windows API QueryPerformanceCounter(), which can return inconsistent results on:

• Multiprocessor systems
• CPUs with variable-speed technologies (e.g., Intel SpeedStep)
• Systems with BIOS or HAL bugs

Seconds(False) uses a different API and is not affected.

Solution

1. Update system components:
   • BIOS
   • CPU/chipset drivers
   • Windows updates/service packs
2. If unresolved, add the /usepmtimer switch to Boot.ini as recommended by Microsoft KB 895980.
   Note: Incorrect Boot.ini changes can make the system unbootable. Back up critical data first.

Additional Information

Microsoft reports this issue on some AMD systems running Windows 2000/XP/Server 2003, but it can also affect Intel CPUs. The workaround has resolved issues for both.