Then there is the ISO comparison on a color chart in the same review. The noise level looks SAME to ME at high ISO.
IMO, the difference becomes apparent at ISO 3200, and the 1D X becomes progressively better than the 5DIII at ISO 6400 and beyond.
Yes. Which is exactly why I'm getting a 1DX and owning two 5D Mark III's. If the 1DX proves to be much, much better, I'll sell one 5D Mark III, save money, and buy another 1DX or if there is a newer camera out above the 5D Mark III I'll look at getting that. High ISO is paramount for indoor sports and for what I do it would be quite idiotic to NOT own a 1DX. Granted I don't shoot above ISO 2000 at weddings because of flash, you don't get the flash advantage in a lot of indoor situations, namely sports. I can't stress that enough.
I will also add that if you do get a 5D Mark III, the IQ is stunning, resolution is fantastic, and you can auto ISO in manual mode at all ISO values. I will always have a 5D Mark III in my bag after having used it for a few months. I've been meaning to post some photos recently because it's so easy to talk on here and wanted to show that yes, I'm actually doing something