Thus spake "Chris" <criro1999@gmail.com> :

>Is a 5AT more fuel efficient than a 4AT, if we consider the same car?
>If yes, in which road condition?
>The number of RPM on a 5AT is different (lower) than a 4AT for the same
>speed?
>
>Thanks,
>Chris
>

In general, maybe. Look at the final drive ratio for the two cars.
The four speed may actually have a more fuel efficient top gear. The
problem is that you'll give up performance for this.