If you use a normal Xojo Timer in your project, you can use periods down to around 16 ms. Even if you select 5 ms, you get about 16 ms. More than 60 action events per second are not possible. See this test project which measures what we get for a timer with 5 microseconds:
Now with next MBS Plugins, we have already prepared a replacement class: WindowsTimerMBS.
This class can provide an action event on main thread much closer to the 5 ms target as you see in this screenshot:
Of course timer can only fire if main thread is not busy, so if you do too much code in action event, the next event may be delayed.
I hope this makes a couple of Xojo developers happy, for example if you want to measure values 100 times per second on a serial port.
PS: In newer plugins, the WindowsTimerMBS class got renamed to TimerMBS.