So I have a stock (hitachi, I believe) 500GB 7200RPM drive in my 2011 MBP, and just purchased a Scorpio Black 750GB WD HD as well as an Optibay to replace the superdrive. I am just wondering which HD I should put in which port? I read the optibay is only SATA2 while the HD bay is SATA3 (?), but I'm not completely sure what that means. The scorpio read/write is faster than the hitachi, and I believe I read somewhere that you want to put the fastest drive in the main slot, however the extra 250GB space the WD drive has would work nicely as my scratch drive for video editing if the speed difference isn't going to be noticeable. Any input would be appreciated!