My Google-fu isn't turning up specifics on this issue - just people saying there are "issues." So I'll just post my question - I've got a late 2011 MBP and with a Momentus XT 750 running perfectly as the main hard drive. I've got a 640 WD Blue in the optibay running perfectly also. I've just ordered an SSD (NewEgg has the Samsung 840 PRO for $199 today!) and would like to put the quicker Momentus in the optibay. And it has my existing BootCamp partition on it as well. What problems may I encounter with this? From what I've read that MPBs older (than mine?) do not support SATA 6 in the optibay, but I figure the drive will negotiate down to 3 and be just fine. I can confirm that the negotiated speed of the WD there now is 3 and the link speed is 6. I'd just do it and try, but putting a drive in the optibay is such a PITA, I'd like to hear from experience before I learn the hardway. Thanks!