Well, for one I'd imagine you can do all ports at once. Or start doing it and allow rest of drivers to initialize their stuff while it is waiting

At least looking in my dmesg on linux all SATA drives are getting ready rougly at same time 0.6 s into boot AHCI driver gets initialized and 3.2 seconds into boot they are all up. Looks parallel too as ordering does not match log order

    [    3.192274] sd 6:0:0:0: [sdc] 500118192 512-byte logical blocks: (256 GB/238 GiB)
    [    3.192277] sd 7:0:0:0: [sdb] 3907029168 512-byte logical blocks: (2.00 TB/1.82 TiB)
    [    3.192277] sd 8:0:0:0: [sda] 5860533168 512-byte logical blocks: (3.00 TB/2.73 TiB)