Optimizing Conway's 'Game of Life'

To experiment, I've (long ago) implemented Conway's Game of Life (and I'm aware of this related question!).

My implementation worked by keeping 2 arrays of booleans, representing the 'last state', and the 'state being updated' (the 2 arrays being swapped at each iteration). While this is reasonably fast, I've often wondered about how to optimize this.

One idea, for example, would be to precompute at iteration N the zones that could be modified at iteration (N+1) (so that if a cell does not belong to such a zone, it won't even be considered for modification at iteration (N+1)). I'm aware that this is very vague, and I never took time to go into the details...

Do you have any ideas (or experience!) of how to go about optimizing (for speed) Game of Life iterations?

I am going to quote my answer from the other question, because the chapters I mention have some very interesting and fine-tuned solutions. Some of the implementation details are in c and/or assembly, yes, but for the most part the algorithms can work in any language:

Chapters 17 and 18 of Michael Abrash's Graphics Programmer's Black Book are one of the most interesting reads I have ever had. It is a lesson in thinking outside the box. The whole book is great really, but the final optimized solutions to the Game of Life are incredible bits of programming.

There are some super-fast implementations that (from memory) represent cells of 8 or more adjacent squares as bit patterns and use that as an index into a large array of precalculated values to determine in a single machine instruction if a cell is live or dead.

Check out here:

http://dotat.at/prog/life/life.html

Also XLife:

http://linux.maruhn.com/sec/xlife.html