Most likely an out-dated SATA BIOS (v4.3.47 hasn't been updated
since 2004). People were having trouble getting the 1TB drives to work on many of these older boards, due to the dated Silicon Image BIOS. e.g.
http://forums.anandtech.com/showthread.php?t=194054
This is what I figured. Searching Silicon Image support I see they have BIOS updates for cards but say they don't support updating the BIOS in their controllers embedded in motherboards. Gigabyte's support for the motherboard seems to be in mothballs. I suppose it's useless to try to get it to work in that machine. I have an enclosure for it. I'd prefer to have it inside for far superior performance, however.
Edit: Looking at that thread I get the impression I might be able to update the Sil BIOS to version 4.3.79. Do you think that's possible? Do you think it might support the 2TB drive?
Edit2: I have no intention of installing an OS on this, it would just for for data, so I'm thinking that all that stuff in the thread about MBR and such don't apply. Is this correct?
Edit3: Found and been reading a potentially helpful thread dealing with my mobo and SATA controller:
http://icrontic.com/forum/showthread.php?t=12464
It's from April 2004, but has interesting information. One of the things that has caught my eye is the advice to run even a single SATA drive in RAID mode and not BASE mode. I've never tried that. I've had issues with the controller (I'm pretty sure the problems are due to the controller) in that I have frequent major difficulties with my HDTV card's software when the data files directory is set to the SATA drive. My workaround has been to have the data on an IDE drive, but they are small. Maybe moving to the RAID driver will help. There are still some issues when running on IDE, but far less severe.
you try a different cable/sata port?
I know the port and cables are working because I pulled the cables off the 500GB SATA HD that's in the PC, which works when using those cables (data and power).