After creating Newton you should set Newtons minimum framerate (which is set to 60 by default). In my case I want Newton to update 100 frames a second. If the game runs too slow, Newton will interpolate the Newton steps to the current framerate.

So in my case (100) I call:
Code:
NewtonSetMinimumFrameRate(NewtonWorld,100);
My DeltaTime is calculated between 0 and 1, so I update Newton by calling:

Code:
NewtonUpdate(NewtonWorld,(1/100)*time_);
where time_ is my Deltatime...

As you can see, I tell Newton to update 100 frames per second, no matter what framerate I have (because I multiply by my delta)...

What you do is telling Newton it should update as fast as the current framerate is, which of course differs from PC to PC... So this is no good idea.

Try my way and tell me if it works better...

Greetings,
Dirk