Hi everyone, I have Googled about ram compatibility, but found no specific answer. What really determines ram compatibility? I think it has something to do with specific memory controller on the board and some 'little' chip beside it. And what I find interesting I that - the same 'little' chip must be on the RAM module. (probably standardized chip or just 'generic' or just some numbers, code, etc..) So, can someone provide more information so we can make a table (geek stuff) to help others. And, I would appreciate information about specific MacBook model (late 2009, - 6.1) so I don't have to open it and search for a needle in the haystack Where I live, 'mac certified' ram module has double or even triple price than regular. Thank you!!