I've made the change to the Idle Power option in the BIOS (can't recall the setting, basically don't have it reduce at all) and I've turned off any suggestion of overclocking in the bios (the AUTO settings) per the Unraid FAQ in the post above this one. I also changed all the SATA cables and I made sure I have no drive on a shared SATA port that is shared automatically with an unused M2 slot.
One of these changes appears to have resolved the issue as I am almost all the way through a rebuild of the drive and I haven't had a single CRC error.
