You will achieve similar results with qualified SCSI and ATA/IDE drives. The only noticeable performance difference might be a slight delay upon playback or recording in large sessions when using an ATA/IDE drive. SCSI is not a requirement with the Pro Tools Free. However, if you are working in multiple studios an external SCSI drive allows easy portability to other Pro-Tools Windows 98 SE systems. If you are thinking about purchasing a SCSI controller for playback and recording with Pro Tools Free, be advised that the ADAPTEC AVA -2906 SCSI controller card is the only supported model for Pro Tools Free Windows 98 SE Systems. We can not qualify the performance of other SCSI controller cards at this time. Review the Pro Tools Free compatibility document available at Digidesign.com for more information.