I just upgraded my RAM to 4GB from 2GB. Just ten minutes ago my MBP was showing that is was using 525MB of 2GB, but now that it has 4GB, it's using up 840MB of 4GB. I'm running the same open applications as I was just ten minutes ago, but now it's using more!? I upgraded my RAM because I use windows via VMWare Fusion, and I wanted to use Vista this time around so I wanted to give Vista a full 2GB under virtualization. I'm just wondering if Leopard is just greedy with RAM when it sees that there's plentiful, or if this really is an unusual behavior. Any input on this is greatly appreciated.