Just be sure to compare the output of the TICK and FREQUENCY to the actual passed time value of the clock. That will only be an issue with unpatched dual-core processors, and dual/quad processors, which use two separate clocks. The end result will be drifting or pure half/quarter or double speed. (Depending on the arrangement.)

But the issue should be nearly immediate, after the first call of the API, and a quick 2 to 5 second check.

Where can I find the help-file for this module?

Even with GetTickCount driving it... it is a valuable tool.

Here is another MSDN page to show some of the issues above.
http://msdn.microsoft.com/en-us/magazine/cc163996.aspx

Focus is on the drift/accuracy related to system state changes, and also dual-core.