this is more of a how does it work question than a looking for advice question. so after discovering how easy it was to install ram on my macbook pro (thank you macrumors forum), i thought why not do the same for my powerbook g4. i just finished upgrading it from 512mb to 2gb. according to the activity monitor (which i only just learned about), with only safari, itunes, and iphoto launched, it says that i'm using about 612mb of ram. what i want to know is how was my computer functioning on only 512mb of ram prior to my ram upgrade (since 612mb>512mb)? i'm just curious cus while i always thought my laptop could run faster, i never thought of it as being slow. thanks for everyone's input!