Originally Posted by elglg
The power requirements aren't the only reason for having numerous power connections. Hence one of the reasons why CPU's etc have an ever increasing amount of pins, they are not just their for I/O etc but the vast majority of them are power and GND. This is to seperate the power for different areas of the chip/board to reduce the EMC effects.
Also the reason for having numerous 12V lines from the PSU isn't just that all the current may burn out the conductors but also because the resistance of the wire = (resistivity x length)/area, so for thinner conductors you get a higher resistance for a given length, so if only one cable was used by the time you got to the end of the cable there could be quite a voltage drop along the cable and wouldn't see 12V at the end...