Digital Photo Professional 2.1 includes optionally selectable noise reduction for both luminance and chrominance (color) type noise reduction selectable in a range of three steps (None, Low, High). In our tests this noise reduction while partially effective wasn't as flexible or as good as that found in other third party noise reduction or RAW conversion tools. You can also see from the comparison below that the camera appears to be applying both luminance and color noise reduction to JPEG images (to the detriment of image detail), it would be nice to have the option to control this from the parameters menu.
In RAW conversion terms the cleanest image came from Adobe Camera RAW with both luminance and color noise reduction enabled (at 25 each; out of 100) although this does mean some detail has been sacrificed. My personal choice would be Adobe Camera RAW's default setting of no luminance noise reduction but color noise reduction at level 25, this delivers the most 'film like' response (luminance grain with no color blotching) and also maintains image detail. I'd suggest that while DPP's selectable NR is a good first step the algorithm clearly needs tweaking, it should have more latitude for adjustment and should be available on the main edit window not hidden away in the preferences dialog.
Note: The following images are VERY LARGE please only download if you absolutely need to.
ISO 3200 (H) image noise reduction test (100% crops)
Details: ISO 3200 (H), 1/25 sec, F4.0 (EF-S 17-85 mm IS @ 22 mm), RAW+JPEG