I just got a macbook, the 512mb of ram it came with just isnt cutting it. I was going to buy another 1gb of ram. I have been told by a few people that it isnt good to have two different brands of ram in your machine. It is best to get a 1gb kit or a 2gb kit not 1gb of one kind of ram and 512 of the stock ram. I have been told that this can result in some system problems. Is this true?