Nikon D3 vs Nikon D3s ISO-wise by Georg Nyman
The "existential raisin" (raison d^etre) of the Nikon D3s is to provide great low-light photography, so with that in mind, be sure to check out the D3 vs D3s ISO Comparison by Georg Nyman at Photoscala (computer-translated).
For more on the camera, be sure to check the D3s hybrid page, which serves as both a snapshot-reference on the camera, and a stock-status page (left sidebar). This is not like our regular camera diaries - it is more of a Web 1.0 static reference page. It is a new format we are trying out.