Devil,

Quite true, the classic CPU versus memory tradeoff. As with all "optimizations", you almost never get away for free.

Personally I would rather waste a CPU cycle or 2 since they tend to be very cheap, and for what I do (mod_perl web apps) a pico second here or there is usually okay, while running into disk swap for memory is not.

In the end, I stick with the old mantra:

Premature optimization is the route of all evil.

- C.A. Hoare (although usually attributed to Donald Knuth)

-stvn