Incredible High ISO Performance!
I did a poor man’s experiment to see how well very high ISO values of the D3 compared to my D200. I was blown away. The end result was that I was getting 640 ISO (from the D200) performance at around 3200 ISO!! This is in the territory of 2 to upwards of 3 stops performance improvement in noise handling!
In the example above, I photographed one of my large prints to use as a gauge for noise. The top half of the image is shot with the D3 at an ISO setting of 2000. In the bottom half, I shot with the D200 at an ISO setting of 640. The noise on the D3 is quite a bit finer, which is easier to clean up. More thorough reviews/tests of the D3 High ISO performance can be found below:
http://ishootshows.com/2008/01/07/impressions-on-the-nikon-d3-high-iso-performance/
http://www.kenrockwell.com/nikon/d3/vs-5d-180mm.htm