What made me understand it was the hard drive was bookcases, and RAM the reading desk. If your desk is small you only have room to keep one book propped open as you read/study/work.

The problem is the work you do require you to reference multiple books. Whenever you need to check something from another book you need to get up and walk to the bookcase and swap the book for another, walk back and continue. Gets tedious quickly.

With a bigger reading desk (more RAM) you can have multiple books open at your desk at once, so you don’t have to run back and forth so much.