In my routine review of the Nikkor family of lens, together with what I have been told by several friends, an identical lens (e.g. Nikkor 50mm F/1.4G) fixed on the DX body out resolves an image compared to it being used on an FX body!
This is verified by typically found MTF50 charts, in both center and corner resolution. It is also said that the full frame matrix has a lower efficiency rating compared to the DX matrix. An interesting read was found to support my findings [here] for this particular example.
Well, this small discovery seems to give DX body owners one more reason to stay put in the DX camp after all.