I have searched around for another thread to address this, but I couldn't find any. I have attached an image of the Activity Monitor, (yes, I covered my name with "User", but the rest of the shot is genuine. As you can see to list is sorted by process memory allocation, and it doesn't add up! I did get 16GB of memory to avoid any Swap Memory! I'm shocked, and well I can't tell any performance hits at all even running 8 processes at 90%+, but still! Can anyone explain this? I am running the 64-bit kernel as you can see, and I am running Sophos to clean out a Windows NTFS partition. (Yes all the other processes below what can be seen have a much smaller memory footprint per the sorting). I'm running an iMac (again with 16GB of RAM), Late 2009 Quad Core i7, that's also obvious (again) from the image since I'm running 8 processes above 90%. Are there processes that are hidden from Activity Monitor? "Top" says about 3100MB are active, makes more sense, but it also reports 16GB in use, 12GB inactive and 25MB free. Again, can anyone explain this? Thanks in advance!