I'm sure everyone here knows about the updates on the 'books. Which got me to think that it's time to upgrade mine somehow. (Was thinking of just selling and maybe getting the new macbook though. ) I'd like to ask which one would give me a more noticeable performance gain? 4gb ram or a 16mb cache 7200 rpm hd? Capacity wise. I still have a good 40+gb so I'm not concerned about the capacity of the drive. Both upgrades will cost about the same so price isn't too much of an issue either. TIA.