I currently have a 512gb SSD in the main drive, and a 1TB HD in the optical, with an OWC data doubler bracket. If I understand correctly, the max drive height is 12.5mm for the opti bay. Also, it can only run a drive that's 3gbp/s. I've also read something about making 6gbp/s drives run at 3gbp/s by modifying the drive firmware. I'm wondering if anyone has experience with this... I'd like to get at least a 1.5tb, hopefully 2tb drive in there.