[ODE] rate for fixed timesteps

[Daniel.Groll@t-online.de]

I use fixed timesteps to run my car simulation game. With a rate of 60
Hz the simulation runs smooth and seemed to be stable but now with
further testing I encountered some stability problems when cars or
objects move fast. Sometimes they seem to break through geometry or
"caught" in geometry. Is this the cause of a relatively low rate of
world timesteps? Or are there other reasons for instability? At which
rates run phyiscs simulations in common?