ZylTimer is a high resolution, long-term Delphi / C++Builder timer component which provides a higher precision than the standard Delphi / C++ Builder TTimer component.
TTimer component which ships with Delphi / C++Builder uses the Windows Message Queue to generate the OnTimer event. Due to this approach it's impossible to get accurate timer intervals smaller than 50 milliseconds.
ZylTimer is a thread based timer and due to this architecture provides a real precision of 1 millisecond which is inevitable in time critical applications.
The OnTimer event is always fired in time which is not available for the standard TTimer, when there are too many messages processed. The standard TTimer component uses the SetTimer API function, so the interval is limited to 2147483647 milliseconds (about 25 days).