i have xp and 512 ram.i have tried setting to values from none to 1 gig or so and notice no difference.
i currently have it set minimum and maximum to the recommended 766mb and it works well for me.
i have been told that setting the values to a set size like this, instead of letting windows manage it,it normally better as the pagefile stays a fixed size.
i have also tried system managed size and didnt see any difference either.
maybe the effect is greater in older operating systems.