Enhance the documentation for QTimer

It would be useful if the documentation for QTimer could be improved with regards to the difference in behavior on the different platforms.

Make the dependency on underlaying OS more visible, and have a table that shows the typical 1ms resolution (or whatever it really is) under kubuntu 9.04, 15.625ms under Windows XP SP3/Vista SP2 with Qt 4.5, etc. how this changes under Qt 4.6, etc.
This would make it clearer how drastic the differences in performance can be (especially when attempting to achieve a 50ms timer tick), and also give an easier sense of when QTimer is an appropriate solution and when another solution is needed.