I enjoy natural light portraits indoors, and often boost my ISO to 1600. I've noticed some stippling in some of those portraits, usually in areas of dark to light transitions, which I believe is noise. Please see linked photograph in area to the left of my wife's head and above my daughter's head, where black meets gray.
I haven't had great success with this particular issue using noise reduction software (including Neat Image and Lightroom 3 Beta 2 noise reduction tools). Lightroom 3 left an unappealing banded gradation in the place of the stippling (second link below). Neat Image left some stippling. However, aside from these light to dark transitions, I've had success with such software.
What I'm seeking is some advice on whether upgrading from my D90 to a D700 would assist in my quest for smooth low-light portraits and remove the noise that I pointed out in the linked photo. I did, in fact, hear from 1 person that upgrading to a D300s would fully solve this issue, but my reading on websites seems to indicate otherwise and it does seem that the D90 should have equal high ISO capabilities.
Can some people with the D700 and/or D300s provide some insight, please?
(above link to default Capture NX2 conversion)
(above link to LR3beta2 with LR Noise Reduction)