I've just experienced that my 4-bay drive enclosure won't accept any of the 3TB SATA-III drives I just bought. It turns out that the enclosure won't work with 6G/larger than 2TB drives. I'll be getting a Mac Pro 5.1 shortly and am wondering if the drives can be used internally or if I can run into the same problems? I'm aware the built-in interface is 3G, but I'm OK with that if I can just use the drives with their full capacities.