Hmm qpieus, USB performance isn't quite up to XP level for me in SUSE, but I do get close to or up to 16X transfer speed, depending on the USB enclosure used. I think maybe that USB hard disk adapter you're using isn't suitable for optical drives, or at least it's not very compatible with the BenQ. Does that TRT work better in XP with the same connection? Scanning doesn't need high transfer rates as it's just transmitting the scan data, not the actual data on the disc (it even works on USB 1.1).

I didn't do anything , but Xubuntu installed the drive as /dev/sr0 (SCSI-device) and not as /dev/hdc (IDE-device). It depends on the hardware and how Linux decides to use it. I'm sure it's possible to "force" it to use the SCSI driver on other installations, but I'm not that good. It would be better if the author of CDSpeed could make some adjustments, seeing as other CD/DVD related programs don't have the same problem accessing PATA drives under Wine.