I'm using the 5900 on a 60" GWIII that's been tweaked to the 9s.(lets talk color decoder, grayscale, enhancements, etc) Making adjustment to 3DNR and MQNR for all intents and purposes has corrected the dithering/noise that I was seeing. For now I'm distracted with thinking how good the picture looks and sounds to stay focused on the actual program.
What's interesting is back in February when I was auditioning a Denon 2900 on a GWIII, it had this same effect. Problem is the 2900 doesn't have the adjustments that the 5900 does. Anyway, the 2900 I bought didn't have this problem on my GWIII. Sounds like the firmware may have been different between the dealer's demo unit and the one that I actually bought or maybe it was broken.
Although I really liked the 2900, I'm glad that I upgraded to the 5900.
Samsung 64F8500, Panasonic 65VT50, Oppo 95, Tivo Roamio for OTA, Dish VIP722, Marantz AV8801 preamp, Rotel Amps, Atlantic Tech 8200 speakers, Seaton Submersive HP, Calman 5, Chromapure, Accupel DVG-5000, i1Display3pro, i1pro2, eecolor colorbox.