i’m far from an expert on the topic but i asked this question myself a while ago and learnt from various answers that AE is a 32bit app which can only make use of 2 gigs of ram. i have a dual processor g5 myself with 4gigs of ram as of recently. the cool thing with having more than 2 gigs of ram as i see it is that i can render with the render engine while i work in regular AE. probably the OS, photoshop and illustrator eat a fair bit of ram too, so having 2 designated gigs of ram for working is great. i have no idea if it really works this way inside that tin can next to me on the desk, but 4 gigs certainly moves the train of programs a bit quicker than before and rendering while being able to work on is not a bad thing either… i don’t think you wasted your money on ram, but as far as i know AE can’t use more than 2, so the rest you’ll use on other stuff… if anyone really knows the exact answer to this, i’d be really happy to know too. cheers/d