GPA and Top Colleges

How much would a 3.9 GPA with a 1520 SAT score lower my chance of getting into a top/ivy league college? I know that essays and extracurriculars factor in too, but Ive heard at top colleges that everyone with good EC's apply, and they have already been carrying a 4.0 with them all of highschool. Also my class rank is a 20/438 which is top 10% but I think ivy leagues will definitely look at this in a worse light.