Adobe Photoshop CS2 Camera RAW 3.1 - Analysis of Crops Out of the Red Channel
Below is a more detailed noise analysis of the image used in my review at dpreview.com.
This is a limited test on the red channel of a Nikon Coolpix 5000 image.
Different camera brands and models may lead to different results.

Opening the Nikon *.NEF RAW file with Photoshop CS2 Adobe Camera Raw 3.1 or Nikon Capture 4.3 results in different noise and grain patterns, even with noise reduction OFF in both programs. Photoshop CS3 results in fine film-like grain that is more visible, while Nikon Capture 4.3 produces a coarser but smoother grain.

Photoshop CS2 with Camera Raw 3.1 removes noise well but introduces waves in uniform surfaces such as skies, common to many automated noise reduction methods. The Filter -> Noise -> Remove Noise command introduces more waves (see Image C).

Nikon Capture 4.3 removes noise without introducing waves but introduces some other artifacts instead.
When using the manual 123di noise removal method on image A, the Photoshop CS film-like grain remains present (but when looking at the RGB image the color noise is removed). When removing the noise from image B, the sky is free of noise and grain, resulting in a very smooth sky. Image F is the best result, followed by E. Of course E and F require more time.
A. Opened with
Photoshop CS2
without any noise removal.
B. Opened with
Nikon Capture 4.3
without any noise removal.
C. Opened and
noise removal with
Photoshop CS2.
D. Opened and
noise removal with
Nikon Capture 4.3
E. Opened with
Photoshop CS2 and with
123di noise removal.
F. Opened with
Nikon Capture 4.3 and with
123di noise removal.
Click here to
view A->C->E.
Click here to
view B->D->F.
"The 123 of digital imaging Interactive Learning Suite" features unique noise removal methods. Click here for more info.