No, there is really a difference between the two even at iso200.....
Really? I test a shot at NSC @ ISO 3200 on D700. I find it just as good as my previous D90 @ ISO 400.
If ISO 200 on a D90 is its base and it's very resilient to edit without causing much noise, I wonder what wonderous picture can a D700 give at ISO 200. Feeling poisoned now....