I'm hoping to buy another gig of RAM soon, but not sure if i need it. I have 1 Gig already. Checking activity monitor when i'm raping my mac with ProTools running a big mix still shows it has some free RAM. more interestingly, there is usualy a large portion of 'Inactive RAM', and i was wondering what this is? Is it stuff that is is RAM that is not currently being used by a program? if so, why not free it up for the current program?