@CodeSmith
This is the case even with PCs, I think it's got to do with the thicker wires causing interference on each other at high transfer speeds, the thinner wires don't have that problem.
Well, you thought wrong. Like Argo pointed out the extra 40 wires are separate ground wires for each signal wire. Check pcguide
Ultra DMA (80-Conductor) IDE/ATA Cables for details.
