Firefox back/forward lag

While I love Firefox, there’s one thing I really really wish it did better (well, there a number of things, but this is my current wish of the moment). I LOVE the way Opera navigates backwards and forwards. Clicking the back or forward buttons loads the pages instantly. No lag at all! Firefox has a considerable lag while it contacts the server again. IE is better than Firefox in this area, but still not as fast as Opera.

Anyone know of a way to get Firefox to act more like Opera, in this respect anyway?