Displacement Mapping Strangeness [BLENDER 2.41]

I am having trouble while attempting some displacement mapping on a 32x32 grid. It seems if I use a gradient map that has curves vertex spikes occur in the render. Also if I set the grid resololution higher the spikes get worse. Roughness increases as resolution gets higher.
The gradient maps I am using and sample renders are listed below…

gradient maps…
sample renders… (last file here is where grid resolution increased)

Anyone have a clue as to how to smooth things out?

Thanks --Andrew

On the last one, nor needs to be turned off and the nor value all the way down for the displacement texture settings

Ok thanks that helped some…
above is the render of puzzle piece after increasing grid res to 128 and moving nor to zero.
Still some roughness here.
Can anything be done about this?
– Andrew

You need a really, really high resolution for perfect displacement, set smooth will help some.

Better yet, get 2.45 and use the displacement modifier and use a subsurf modifier after that.