The 305S is the earlier generation of DVD player and is very loud. The latest the 106S (ATAPI) is much quieter, less than half as loud as the 305S. I have an all SCSI system and wanted the 305S to keep everything on the SCSI bus, but it's so loud, I traded it in for a 106S. Lower CPU utilization and better performance than the SCSI drive. I never thought I'd use an EIDE/ATAPI device, but it's in the machine and coexists very well. With WinDVD, movies are smooth and it's faster at ripping CDs than the 305. Go figure.