When I get my macbook soon I want to upgrade the ram to at least 1GB, and I wanted to know what configuration would be best? Upgrading on apple's site to one gig (512 x 2) or buy a one gig stick to replace one of the 256MB sticks (1GB x 1, 256MB x 1; 1.25GB total)? Which would offer best performance? I'm asking because I keep hearing that dual channel is better, and then I hear that it doesn't matter. I just want the most bang for my buck.