Why use GetHashCode() over Equals()?

Question

HashSet.Add first compares the results of GetHashCode. If those are equal, it calls Equals.

Now, my understanding is

Answer 1

Because if an algorithm wants to test if 1 object is already in a set of 1.000.000 objects, it has to call Equals 1.000.000 times, but GetHashCode() just once (and a few calls to Equals to eliminate objects which are different though having the same hash code).