I have a C2D Duo 2.53 (late 2008) with 4GB of RAM. When I run iStat, it lists four categories of memory, and I don't understand what they mean. Wired Active Inactive Free My question is this: What is the difference between "inactive" and "free", and what's the difference between "Wired" and "Active"? I keep running out of memory, and it's saying I always have between half a gig and one gig of "inactive" memory, while almost nothing is "free" (5-25 MB). ?? Then pinwheel madness ensues. Keep in mind I'm not running *anything* memory intensive. My open programs at the time were: iTunes, Pages, Calendar, Safari, Mail, Firefox, and Preview. Just wanted to get insight from the pros. haha.