D600 vs. D3200: Low ISO IQ with same lens

Hello all,

I am strongly considering the D600. Since FF is not a value in itself for me, IQ at normal ISO should be better than on a DX camera with the same mp count, say the D3200 (or the future D7100 and D400).

How is expected sharpness of the 12-24 AF-S on both cameras at ISO 100?
D3200 set to 12mm, D600 set to 18mm.

The same for the 24-85VR. D3200 at 24mm, D600 at 35mm.
Will the D600 produce sharper, better pictures?

Regards,
Fred