I've been looking into ordering a Macbook. The cost at the Canadian Education store for 2x512 is $115. My other option is to buy a 1gb stick, for 1.25. However, the best price I've found is $150 plus shipping. Cost is an issue. I'm not sure that the benefit of 1.25 single channel over 1gb dual channel is worth 50 bucks, if it would even be noticeable. Currently, on my PC, under windows I have a typical ram usage of about 600, and under linux a bit less. What usage could I expect from OS X?