I was reluctant to try it out since I had constant spinning beach balls and consistent freezing. But after trading out the previous MB with this new MBP, I decided to install the same hard drive that I had in the old MB into this new MBP. I did a fresh clean install without any cloning or Time Machine restore. After getting everything setup and [mouse, background and email settings], I updated all of the software updates that were available for my laptop. Once those were up and running I had FINDER open and clicked on the documents folder and the beach ball started spinning. I also noticed it almost as soon as Itunes was up and running. I haven't had any freezing yet like my last MB but I'll give this a few days to see how it works out. I'm hoping that Apple [or someone here] can figure out why a lot of us are having problems with using a aftermarket hard drive along with that firmware update.