Quoth Alex Dumitriu:
>
>One other thing to check (and I know this is berrating the obvious):
>
>Make sure you're using 80 conducter cables, not 40 conducter, other wise
>you will surely get knocked down a few UDMA levels....

Yup, I was actually using the one that came with the card. :D

Even with a 40 conductor cable, it shouldn't have been knocked down to
PIO modes.

The same cable/drive is working again on the mainboard's controller, at ATA/66.
The controller being:
pciide0 at pci0 dev 4 function 1: VIA Technologies VT82C596A (Apollo Pro) ATA66 controller
pciide0: bus-master DMA support present
pciide0: primary channel configured to compatibility mode