It probably mattered to few that Apple implemented SATA 2 optical drives in the current series of Macbook Pro 2011. If you bought a new MacBook Pro in the last 2 months, then you have a SATA 2 optical drive, but if you bought a MacBook Pro 2011 in the last days or in the last week then you might be among the lucky ones who have a SATA 3 optical drive. Recently Apple started to implemented this new optical drive in the MacBook Pro and for now only the 17-inch model has been discovered to change. Theoretically, the difference between SATA 2 3Gbps and SATA 3 6 Gbps is given by doubling the transfer speed when copying something from a DVD. I say theoretically because the speed also depends on the other internet components of your MacBook.
If you don't have SATA 3 in your MacBook Pro, don't worry because you won't be affected by this at all. At the moment, no one knows for sure when Apple started using SATA 3 optical drives in MacBook Pros, so if you buy one now, you cannot be sure that you have a new optical drive. If you still bought a MacBook Pro in the last few days, then you can check the optical drive using System profiler from the Utilities folder.
