My early '09 24" iMac has been running great, especially since installing 10.8. It has a base 4GB RAM config but I think both slots are being used (2x2GB). I'm not a heavy user by any means although I do the occasional marathon photo editing while multi-tasking. With RAM being so cheap these days I thought I might as well upgrade to 8GB (2x4GB) but I'm wondering if the upgrade will be noticeable. That's when I started reading up on "Activity Monitor", specifically "Page outs". So from my limited understanding of this, it seems if one gets a lot of Page Outs then it's time for more RAM. The thing that's confusing is how much is "a lot" of page outs? Currently I'm seeing generally less than 1GB page outs, typically in the 200KB-600KB range. Would more RAM help or should I not bother?