As of 2017, modern SSD drives are that fast e.g. a simple Toshiba A100 - 120 Go,
read ~ 550 Mo/sec (SATA III 6 Gb/s) write ~ 480 Mo/sec (SATA III 6 Gb/s)
whie the SATA max speeds are,
SATA revision 1.0 (1.5 Gbit/s, 150 MB/s, Serial ATA-150) SATA revision 2.0 (3 Gbit/s, 300 MB/s, Serial ATA-300) SATA revision 3.0 (6 Gbit/s, 600 MB/s, Serial ATA-600)
therefore it’s truly preferable to choose an SATA II laptop or T61 bios mod over a T60 SATA I so you can really take advantage of the SSD performance upgrade.