Babies tend to be much more efficient starting at around 6-10 weeks. Some can be really fast, my dd was usually done in 5 minutes.
You need to look for output not input. That is if he produces 6-7 wet and 2-3 dirty diapers within 24 hours, if he is gaining weight, is active, happy and so on.
Also, if he can go at least 2 hours between feeds, I would say he is doing as most babies do
.