Oh. Well, I was\ prepared to take this seriously until you mentioned DxO. DxO reckons the unloved Nikon D200 has lower noise than a 5D! (Or was it some other absurdity? Can't remember. In any case, there are lots of them.)
* Warning. The above post is designed to be provocative. This is something I learned from a bloke named Kym. I am actually quite prepared to look at this seriously when I get a minute, but (obviously) I'll disregard any "evidence" presented by DxO.