I replaced my MacBook Pro's internal drive with an SSD and used the OWC Data Doubler to put a 750GB WD Black where the optical bay used to be. I've noticed, however, that the WD Black won't spin down. Even leaving my Mac idle for a long time I can feel it rotating. In Energy Saver "Put hard disks to sleep when possible is checked". I'm at a loss at what to do here. Thoughts?