There is only one PowerDomain 2940 card from Adaptec. However, versions of the firmware prior to 2.0 did not support Ultra SCSI, only Wide.
Cards with older versions of the firmware can be updated to support Ultra SCSI by flashing the card with the new firmware, which is available from Adaptec's site at
http://www.adaptec.com/support/BBS_Mac.html.
However, there is a minor bug in firmware revision 2.5 which causes the PowerDomain card to report in the PowerDomain control panel that it is a 2940W instead of a 2940UW. While the card reports itself as supporting only Wide, Ultra SCSI remains active.
Apart from this minor issue, the card will perform as expected in Ultra mode without incident.
To enable Ultra SCSI, select "Set Target Options" from the "Board" menu in the PowerDomain control panel. In the lower left corner, a box should be available for toggling Ultra SCSI support.
If the box is grayed out, the firmware will need to be updated to version 2.0 or later to support Ultra SCSI.
Machines Affected: All