It's a bit like row vs column store.

If there are two lists, in the first example, you're doing:

    a1 -> b1 -> c1 -> d1
    a2 -> b2 -> c2

In the 2nd example, you're doing

    [a1, a2]
    [b1, b2]
    [c1, c2]
    [d1]

Visiting the same number of nodes, but because the nodes are referenced from an array, when you load `a1` you're [probably] also going to load `a2` into the cache.