JUST DON'T DO IT.
The reason is: if you have a timer event let's say every 0.01 secs (means 100 times/sec) and you have the VSync turned on, the max FPS is 60. Actually, the timer seems to be called only once for every frame even if it has expired 2 times.
EG:
-you are playing at 50 FPS;
-you expect your timer doing something 100 times per seconds;
-you get your timer triggered only 50 times per second;
-speed is divided by 2
or whatever else like adding scores, every kind of calculations and so on.This should be fixed by calling the timer untill he has been triggered all the times it should have. I know that it is risky because you can fill the CPU, but this should be the way it was intended to work I think
However it is not high priority: I was using this kind of speed only for testing a project.
And I wasted something like 35 mins on it :/