I've got three HDs on my Mac Pro 8 core, two are SATA drives with two different bootable OS installed. The third drive is an SSD( my main drive ). On random boot ups, the computer often stalls. if I pull the SSD, I can get it to boot. After several boot ups, I'll plug in the SSD and it'll boot up just fine. The SSD is a fairly new OWC 6G. That drive has all my authorizations and after it's able to boot up, it works flawlessly. I've re installed the OS ( Mountain Lion ) a few times already. Short of sending this back to OWC for testing, I wonder if anyone else has had this experience.