Having a good memory is an underrated part of what we generally consider as intelligence. It's the foundation of pattern matching and abstractions. It's speed up for things you already solved before.

Memory + abstraction capability is a more important factor in human intelligence than thinking speed in my opinion.

When facing a novel situation or problem if you can recall a structurally similar one you can better predict how to solve it or how to find new interesting questions to ask.

We've had hard drives for a while now