Hey everyone, I know this issue has been addressed here before, but I cannot seem to find a satisfying answer about what exactly do I need to do to make everything work flawlessly. I have a 15" MacBook Pro 5,3. I previously had a Seagate Momentus 500 GB 7200 rpm originally installed by Apple. As it started freezing up a couple weeks ago, I decided to order the Western Digital Scorpio Black 750 GB 7200 rpm WD7500BPKT. I switched the drives and initiated a clean installation of Snow Leopard from the DVD that came with the laptop. Of course, before that, I formatted the WD to Mac OS Journaled (Extended). Even though the installation was successful, it took around 7 hours to finish and now, even though OS X is installed on the WD drive, it is running way too slow to do anything and I get the beach ball basically every time I click something. I've read about a firmware downgrade, about turning SMS off and about some other things too. I haven't downgraded the firmware but I did turn off SMS, which obviously didn't help. Please tell me, either from your own experience of from someone else's, what do I need to do in order to get this drive to work properly? Thank you very much in advance, I appreciate any kind of help.