I am thinking about upgrading the memory on my iBook, which I purchased before the last revision on the laptop in 2005. My iBook has 256MB memory built in, and I am thinking about upgrading to 1GB. However, I was wondering whether I should use PC2100 or PC2700 memory SODIMM RAM. According to Mactracker, my iBook supports PC2100 RAMs and PC2700 RAMs natively, but PC2700 chips can only run up to 266Mhz on my iBook. Which one should I buy?