I attached the drive to SATA port 3 on the motherboard (removing data drive already attached there), and started a PreClear, for 2 cycles (this was early Monday morning, around 5 am). It finished successfully this morning about 3, so it seems the drive is fine, and the add-on controller is not. Thanks to you and Omid for pointing me towards that.
The storage controller I'd been attempting to use has only 2 ports, one of which is in use and has been working fine, but I need a port in which to connect the data drive I removed from motherboard SATA 3. Is it safe to assume I should expect the same problems if I tried plugging the data drive into that second port, and should just purchase a new controller?
Also, what's an HBA (I'm still quite ignorant with much of the terminology, etc)?