No, a single solitary Hard Disk could not absolutely use SATA III bandwidth, due to the fact most hard disks composing bandwidth could not be higher than 150MB/s, and looking through bandwidth couldn't be previously mentioned 300MB/s, so the SATA III 6Gb/s=6000Mb/s=6000/8MBps=750Bps couldn't be totally used. Slower than NVMe: SATA https://supertop-shop.com/sata-iii-hard-disk/