| Method | Average Resolution | Max Error | Overhead per call | |--------|-------------------|-----------|-------------------| | GetSystemTimeAsFileTime | 15.6 ms | 15.6 ms | ~40 ns | | QueryPerformanceCounter (relative) | ~100 ns | ~1 µs | ~35 ns | | Patched GetSystemTimePreciseAsFileTime | ~300 ns | ~2 µs | ~120 ns | | Native Win8+ version | ~100 ns | ~0.5 µs | ~80 ns |
typedef VOID (WINAPI *PFN_GetSystemTimePreciseAsFileTime)(LPFILETIME);
When these patches are installed on Windows 7: getsystemtimepreciseasfiletime windows 7 patched
// Path B: Windows 7 "Patched" Native API // NtQuerySystemTime returns the time in 100-nanosecond intervals (same as FILETIME) if (g_NtQuerySystemTime)
Are you and need high-precision timing?
Advanced users often use third-party "compatibility layers" like
LONGLONG llPreciseTime = llBaseSystemTime + llElapsed; memcpy(pFileTime, &llPreciseTime, sizeof(FILETIME)); | Method | Average Resolution | Max Error
printf("High-Resolution Timestamp: %llu\n", ull); return 0;