I have a question regarding the actual maximal amount of RAM you can use with the Rev. H (Mid 2009) Polycarbonate MacBook (model : MC240*/A). The thing is, this specific model is nowhere to be found on the table of the http://guides.macrumors.com/Understanding_Intel_Mac_RAM page. This was the last original polycarbonate design MacBook and the only of its kind to use 800 MHz PC2-6400 RAM. It also had a Penryn Core2Duo and a 1066Mhz FSB. According to the table linked above it would mean that the actual RAM limit is of 4 GB. That is if you ignore the fact that the table says there is no such MacBook. On the other side MacTracker says this model can accept up to 6GB of RAM (which would be the equal amount older MacBooks with a 800Mhz FSB accepted). Note that the same question should be asked for the older Rev. G (Early 2009) Polycarbonate MacBook (model : MB881*/A), which also has a 1066Mhz FSB but uses slower 667 MHz PC2-5300 RAM. If anyone could enlighten me, it would be greatly appreciated.