well... Actualy I also want to interpolate the drawings.

I know, that no one would cap at 5 FPS - I just did for testing the collision.
Thanks for your answers yet - another possibility in for me was to calculate the optimal time like 1000ms/60 for 60FPS = ~16.
Now I sum up the delta times for every update and do the update when the sum >= 16.
But I feel like wasting resources as this would render duplicate frames without changing anything.

I will try to implement fixed step timing. Anyone ever did this within the Slick Framework?

I've read the Game-Loops Thread (http://www.java-gaming.org/topics/game-loops/24220/view.html) today and I'm curious about the var step timing regarding collision detection.
Let's say I've got a pretty decent PC, capping the fps at 60 fps and I move a primitive like this:


Now this should run fine on most machines and it will stutter if I cap the FPS at 5 Fps.
When I now test pixel perfect collision with the 5 FPS Cap it is not possible to get the same accuracy as I get with more FPS.
Are there any tricks to solve this? Or do I need fixed step timing?