Magic Lantern published a video below illustrates the difference between normal RAW and Dual ISO RAWwith the Canon EOS 5D Mark III camera.
Take a look at the shadow noise reduction in the Dual ISO RAW example, it is very impressive. The video was produced under adverse condition so much better results can be expected when used under normal conditions.
Also this is part of Magic Lantern increasing the dynamic range of the EOS 5D Mark III and EOS 7D by 3 stops using a dual ISO technique.
