How can I adjust Cycles material displacement amount? The experimental feature set in Blender 2.75 includes an option to allow the displacement socket of the material output node actually displace the mesh instead of acting as bump-mapping.



However I can not figure out how to control the actual displacement amount.  Simply adding a math multiply node does absolutely nothing.



So how can I change the actual displacement amount?
Remember this in an experimental feature it doesn't update atomatically every time. To force update Exit Rendered View to solid view and switch back to Rendered view. Or Render with F12 and you'll see the difference.

With True Displacement x10


With True Displacement x20