I took this original shot at 6400 ISO with lots of noise:

Original

And using Topaz DeNoise converted the shot to this:

DeNoise, BW conversion, soft vignette

Topaz DeNoise allows one to get rid of the noise without destroying the clarity of the photograph.

If you click on each of the images they will open in a separate window where you can examine the larger image. I am particularly happy with her whiskers which still maintain their detail, rather than turning into a blurry mess (which is usually what happens with most “remove grain/noise” options in processing software).