What do you see? I see a whole lot less noise, but there's also certainly nothing like the same sharpness. We don't have any details from the poster about fstop, settings, lenses etc. There's a blog page in Japanese about the shoot, but with the google translate I'm afraid I'm not getting any details.
EOS 5D Mark III ISO 12800 MOVIE
There is however this image of the two cameras side by side:
(cover photo credit: snap from the video)