I had no problems whatsoever with a 500GB drive and a Sonnet ATA-133 card, nor with a Sonnet ATA-66 card, years ago. It has been a long time, but I seem to recall something about needing to initialize the new drive as a SCSI device rather than IDE. I have not read the manual recently, so this may be totally off the wall, but what may be happening is that your machine is trying to initialize the drive as an IDE device rather than as SCSI. In my case, I did the initialization in an 8600, so Drive Setup was expecting a SCSI device. The G3, of course, is a very different animal, and that may be the problem. Weren't these cards designed specifically for machines with no IDE bus?

Some suggestions: 1. You could try formatting something smaller, like an old 10GB drive, and see how you get on. 2. You could connect an old scsi drive to the G3's scsi connector, install a system, and try the initialization from it. 3. You could do the deed in an older beige PPC like I did.

The other obvious question is master/slave jumpers, but I take it that you have that covered.