I have been using macbook with 1.5GB ram (1GB + 512MB). Normally, I run a lot of application at once. For example, safari, netnewswire, itunes, vmware fusion, adium, and many widgets. In the end, many of those programs become not responsive, especially if I run the Windows XP using vmware fusion. I was wondering if 1.5GB of ram are not enough for my need. My question is if I replace the 512MB with 1GB of ram to make it total 2GB and running dual channel mode, would it be faster and make all the program responsive? Does adding more 512MB will make significant difference? Here I include screenshot of my memory status.