The difference in SATA cales

Virtually every testing organization that we're familiar with has reached the same conclusion as the one referred to you by McHenryB, i.e., there's no difference in data transmission rates between SATA II (3 Gb/s) & SATA III (6 Gb/s) cables. And based on the informal (real-world) tests we've done over the years comparing those cables we've come to the same conclusion.