There is a well documented problem with running a 6Gb/s SSD in the Optical bay of the 2011 15 and 17 inch macbook pros but apparently you can run a 3Gb/s SSD (i.e. a sata II version) fine but I haven't actually read of anyone doing it. I'm about to spend a lot of money on importing an OWC 960Gb Electra 3Gb/s SSD from the US to England so would love to hear of anyone that is running one successfully (that is any 3Gb/s SSD). There is one other point to make though. Apparently Apple varied the optical bay connection on their 2011 MacBook Pros (15 and 17 inch) between 3Gb/s and 6Gb/s connection speeds (i.e. sata II and sata III). I have the 6Gb connection speed (which ironically is the one that definitely won't work with a 6Gb/s SSD but should work with a 3Gb/s SSD - I think some of the 3Gb/s connections ones will work with a 6Gb/s SSD but running at 3Gb/s!). Hope this all makes sense and would be great to get confirmation.