It looks like those new MacBooks might not be limited to 4Gb of RAM like Apple says on its website. As people who run a Mac Mini with 4Gb of RAM , we can attest to the fact that Apple’s RAM specs are artificially set and might not always be the gawd’s honest truth.
While we don’t yet have official confirmation from NVIDIA (snap!- now we do), the 9400M chipset seems like it would be able to support much more than 4Gb. Some will argue that it is a 32-bit chipset, thereby limiting the amount of RAM to 4Gb. Not true. The desktop equivalent 9300 32-bit chipset maxes out at 8Gb of RAM. They would be unlikely to limit the max RAM on a higher model chipset.
Oh, and you can pick up a few 4GB, 204-pin SODIMM, DDR3 PC3-8500 memory modules from Crucial for $590/each. What a bargain :/ Anyone out there have anymore insight?
UPDATE: NVIDIA PR got back to me (on a Sunday no less!!) The definititive answer:
Yes! 8Gb MacBooks should be no problem:
Yes, an 8GB system can be built using two such SODIMMs after the memory is qualified with GF 9400M.
I’m curious why you were thinking of loading up on memory? In terms of gaming perf, going from 4GB to 8GB of system memory would have little to no effect.
Perhaps Apple is waiting on 4Gb Modules to come down before offering it as an option?