i had pused the slide to 8 for luminance in lightroom. i suck at cleaning up noise lol. here are the same 3 pics unedited . i did lower the exposure 0.3 on the 12800 one to try and make the histograms look the same for all 3 but no other changes made. shot as raw. high iso noise reduction is turned off in camera.
3200 unedited by sedwards679, on Flickr
6400 unedited by sedwards679, on Flickr
12800 unedited by sedwards679, on Flickr