1d mark IV question about tracking ,please help

Hi

i'm a 5d mark2 and 5d happy user

i would like to buy a camera to shoot sport soccer and ,ski and so on

i'm thinking about to buy a 1d mark IV

a friend of mine suggestd me to buy a 7d he told me the af is the same ,it's a poor version or cheap version

well i don't know if the 7d has a poor/ limited version of the 1d mark IV

what i know is that they are 2 different cameras! with different price

i have no great experience in the sport shooting what i'm interested is about the tracking

i tried a D300s , and i found easy 3d tracking i guess it uses colors to track the target

well my question

is there a similar tracking in the 1d mark IV ?(or 7d)

how does the 1d mark IV track the subject ?

really i appreciate evey kind of advises

sorry for my poor english

have a nice day
cheers