Issue with Displacement!

I have recently been following Blender Cookie’s Shader Forge series.
Just when I had tweaked the snow shader to its finished result… I tried to render and found the below image.

on the left is the preview render while on the right is the actual render.

  • samples are the same for both
  • subsurface modifier is same for both

I’m using the experimental feature set with the displacement method of ‘true’.
At first I would assume this would be a bug from this however Kent Trammell who presents the tutorial does not have this issue.

*I did note that while following the tutorial the default node settings for Trammell resulted in something far closer to the right image - he had to tone down the effect… I didn’t. This leads me to believe the right image is what should be showing and not the left.

Anyone have this issue, or a way around/to fix it?