Luke from iFixit.com was kind enough to test out a new NVIDIA-based MacBook Pro with 8GB of RAM (two 4GB chips) to see if the earlier reports were true. NVIDIA representatives had stated that the new chipsets used in the MacBook and MacBook Pro could support up to 8GB of RAM. Previous generation MacBook Pros could only reliably support up to 4GB of memory.

Preliminary results show that while the new MacBook Pro did recognize the entire 8GB of RAM, during actual usage, the computer appeared to be limited to 4GB:

The machine would hit an invisible wall at 4GB and act like it had run out of memory. In the larger screenshot, two instances of Parallels can be seen (both set to 2GB of RAM). The second instance, however, only occupies a small portion of RAM expected. It’s unclear why this limitation exists, as Mac OS X is able to use more than 4GB on Apple’s Mac Pro. As a result, MacBook and MacBook Pro owners should not expect to be able to upgrade to 8GB of RAM at this time.

iFixit has posted a disassembly guide for the new MacBook Pros including RAM replacement and will post updates about these results after further testing.

It is possible that Apple has locked in the restriction of 4GB of memmory awaiting the release of Snow Leopard. As a sells pitch of sorts. Upgrade to Snow Leopard for $129 and unlock the capability of 8GB of memmory on your MacBook Pro Late 2008 model.

Will just have to wait and see what happens, if anything.