The new MacBooks aren’t working well with 3rd party RAM. I tried Patriot DDR3 PC3-8500 1066Mhz RAM. Others have tried RAM from Crucial and OWC. Check out this thread at Apple’s discussion forums to keep up with the problem.
The good news is that the official Apple 4GB RAM seems to work fine AND they are charging a very agreeable $150 (after buying back the original 2GB the MacBook comes with).
Hopefully, a firmware update will come along to resolve the issue.
I installed new RAM and a new hard drive in my late 2008 MacBook.
The RAM didn’t work. Based on the responses to my post on the Apple discussion board, the new MacBooks are extremely finicky about their RAM. PC3-8500 DDR3 1066 Mhz may not be the only qualifications required…
The hard drive did/does work. It’s a Western Digital Scorpio Black 7200 RPM 320GB drive. The installation steps in the MacBook owners manual are incomplete, though. You’ll NEED a #0 phillips and a Torx T6.