Back when the new Macbooks and Mabcook Pros were first dissesembled
it was pointed out that the chipset looked like it could handle 8 GB or ram. Unfortunately after testing the theory it was discovered that no, they can't.
More testing has proven that the Macbook/Macbook Pro can handle a healthy 6 GB of RAM; two GB more than the 4 GB that Apple says it can handle.
When 8 GB was tested