I have a 2010 MBP (both HDD and ODD are SATA 2) so in terms of speed it doesn't matter where I put my SSD. I've been trying to figure out what the best location is for the SSD. On the one hand, I've heard that having the HDD in the optibay is bad because of vibration, noise, lack of SMS, etc. This seems pretty straightforward. Then on the other hand, I've read that having the SSD in the optibay can cause boot issues or problems with sleep due to how it is powered up/down. Can someone please confirm the following - 1. Does the Optibay fit the stock Apple HDD snugly? Is there any wiggle room at all? 2. How necessary REALLY is the SMS? My SMS seems to literally go off every time I pick up my MBP and move it somewhere, making me think that it's overcompensating quite a bit. I find it hard to believe that regular movement like this is going to cause any problems. Obviously, dropping the MBP or whatnot is a different story, but that's neither here nor there. 3. Noise/vibration - is it super noticable? If I do put the HDD in the optibay, I plan on configuring it so that it's accessed as little as possible and sleeping when not in use. The HDD is going to be used only for backups and media storage, so it doesn't need to be accessed very much at all. 4. Any other factors that dictate the best way to position my drives? From what I've read, both sides pose good arguments and there appear to be just as many people with one setup as the other; hence, I'm still undecided. My SSD is arriving tomorrow, whereas I have no idea when the Optibay is being delivered. I'm itching to install the SSD right away in the HDD's spot and do a fresh Lion install Thanks in advance!