In another thread, I've asked about heat/noise between the 13" MBA and 15" MBP. But I've been wondering about RAM as well as I contemplate replacing my macbook. I've heard that the typical rule of thumb is if your pageouts to pageins ratio is below 10%, additional RAM won't help you. It's been just 24 hours since my last restart (I had to update some software otherwise I often go several weeks before a restart), and my pageouts are 18.5%. I have the usual suspects running: Safari (10-15 tabs open), Excel, Powerpoint, Skype, Transmission, Adium, and Windows XP via VMware Fusion (with other versions of PowerPoint and Excel running). I also briefly streamed some Netflix earlier today and had NPR's radio player in the background. I know the SSD is a much better solution for virtual memory than a spinning hard drive, but I also seem to remember reading that RAM is still many times faster. I don't think that I'm a power user as I don't process videos or anything, but I don't really want to change my habits to accommodate the 4GB limit. (And will I pageout more in the Air since the nVidia chip hogs 256MB?) Can anyone comment on whether they have similar or higher pageout levels and whether the Air is up to the task? Or at these pageout levels does it mean I really should get an MBP with 8GB of RAM? Thanks in advance for your thoughts.