my first computer i owned had 32mb running win95.
it churned. bigtime!
then i upgraded to 64mb and the churning halved
my cellery 500 had 128 and win98. still churned on games like UnrealTournament.
had to go back to a p2-300... upgraded to 256mb. slow, but virtually no churning. memory was the only thing saving that machine.
now i have 512. only churns when i start editing 300+Mb wav files
you WILL see a difference between 128 & 256, specially with modern games.
256 to 512... probably not, unless your really doing big stuff.
"i love the smell of Overclocking in the morning!" Says my Hamster.