How much help is a perfect score?

What’s the difference between a 35 and a 36 or a 1590 and a 1600?
I know standardized tests are an important part of admissions, but how much weight does it really have when your score is up there?

None.

Not much for those scores but do realize that acceptance rates hovers around 30% for top schools.

The differences you cited are very small and a perfect test score does not guarantee admission. You probably would get your picture in the local paper. College admission depends on multiple factors.

While I agree with what most said above, a perfect score is IMPRESSIVE. For example, in the graduating class of 2015 there were 10,094 students who got a 35 or better ACT composite score (0.52%) and only 1598 students who got a perfect 36 (0.08%). But if you got a 35 I would never sit again to try and get the 36. Having said that, if you look at the common data set for many top schools, I seem to recall that Rice had a range of 32-35 for the ACT composite, with 35 being the 75th percentile. So in that case, I would feel better with the 36!

No difference.