Found this.
1. Oct 22, 2009 12:18 AM in response to: BahiPara
Re: Luminance noise reduction
Luminance noise reduction is only disabled for photos using the new process version - newly imported photos without existing settings.
Photos that are still set to the old process version show a warning triangle in the histogram, and they still use the old routines which haven't changed.
The Edge Detail slider refines the edge detail in extremely noisy high iso images, so you won't notice that on lower ISO files.
PhotoByMark added 0 Minutes and 24 Seconds later...Double Post Merged Below
Oh here is the link.
http://forums.adobe.com/thread/510370?tstart=0