I own a Precision 7520, came with a 500GB M.2 SSD and I added a Samsung SSD to the HD bay. Looking in the BIOS under System Configuration>Drives the Samsung is on SATA-3, the M.2 is listed as M.2 PCIe SSD-0. And checked by default is SATA-0 & SATA-1. They are not mentioned in the Owners Manual. For the moment I have unchecked them as there is no point in the BIOS looking for non- existent drives. Is it possible to use those HD ports? i.e. is it possible to add hard drives to utilize SATA-0 and/or SATA-1? Where are the connectors located? Or are the BIOS selections for SATA-0 & SATA-1 meaningless?

Thanks for any light you can shed on this!!