D800 is a great camera but one must be absolutely blind not to see that noise level is ok up about ISO 1600- definitely is worst than what can do both D4 and 5DIII. DxOMark tests are completely irrelevant – do not take them seriously. Either the number 800 (and a few others) make a magic in there eyes or they get paid by Sony/Nikon dealers.
I'm really sorry for you DxoMark guys; I'm not going to visit your web anymore and going to turn all my friend of you.