TimerResolution is an application to change the resolution of the default windows timer. The standard timer on Windows XP can vary between 10 and 25 milliseconds. Therefore if your code uses a timer or sleep value less than the timer resolution on your system you won't be getting the results you expect.
The timer resolution will be globally changed while the application is running and will revert to the previous value when it is closed.
1ms timers are achievable using this application