I am not using AIS, just Pro, so my commit size is only ~47M, A firewall looks at packets, while an AV usually looks at the files, so the memory requirements are a bit different. Does your memory go up and down while you are watching Task Manager for a while? Don’t know how XP and 7 compare, but have heard 7 has a much improved memory manager. What happens when you turn off Vegas? One reason for having lots of memory is to be able to run programs much more efficiently and not needing to use virtual memory and shuttling things in and out.