Oh, I believe the most recent 2TB WD Green drive that I purchased was of the 6gb/sec variety. One benefit I found with it, compared to the older 3gb/sec stock, is that the 6gb/sec model correctly identifies itself to the operating system as a 4KB hard sectored drive.

That's useful for Linux, as it saves having to do manual partitioning to achieve 4KB alignment. The partitioning tools can automatically do that since they now see the real characteristics of the drive.

Cheers