Re SCSI, recent Intel drivers report SCSI for everything now, partly because nothing uses that info. Although I think that is not completely accurate, but close enough.
Have you tried different media? Some drives simply burn better with certain media. If you really want to faff around there are utiliies which dump the drive's burning profiles. If you use a CD which isn't listed, the drive either does a quick test or makes a guess. If you media is off-brand, the media may ID itself as a popular brand it performs similarly to. The problem is, cheap stuff may be mis-ID'd.