Why do ATX Power Supplies Have So Many Parallel Connections?

[Posh]

Hi all,

I've recently been tearing down various ATX PSU's for use in other applications, and after cutting down a few forests worth of wires, I've been wondering why all the parallel connections are needed at all?
I understand that the motherboard connectors have multiple pins that need power to be delivered, but why use multiple grounds and power pins in the first place?
Surely it would be more economical and 'clean' to simply use less wiring at a thicker gauge if resistance is the issue...

Cheers,
Posh

[tautech]

To carry the current, nothing more.
Check the current capabilities of such a PSU and then try to put all that current down just one of those conductors, sorry it won't happen.
Now think of all that current flowing through just one pin of those multi pin connectors, again: won't happen.
Further, think of all that current terminating into just one PCB trace: won't happen.

They're a computer supply not a BBQ. 

[Phoenix]

Surely it would be more economical and 'clean' to simply use less wiring at a thicker gauge if resistance is the issue...

A lot easier to route, terminate and connect multiple smaller wires to a pcb.

[Alex Eisenhut]

Pretty sure that a loom of smaller wires is also a lot easier to bend and route inside a crammed PC case.