5d mark III vs 1d mark iv auto-focus comparison

I am considering buying a used 1d mark iv and am curious how the auto-focus will compare to the 5d mark III considering the price of the two cameras are the same buying a used mark iv. I know the mark III is 6fps compared to 10fps with the mark iv but if its auto-focus in sports situations is superior (sharing auto-focus components with the 1d x) I think the reduced frame rate would be fine. I'm curious to see some comparisons on that once reviews start coming out.

any thoughts on this?

i should add I currently own a 5d mark II and a 1d mark II and want to replace the 1d body. So the full frame sensor of the 5d and resolution are not a consideration nor is video, for how much I use it the 5d mark III's improvements don't interest me too much at this point.