One cable for the HDs, one cable for the flop/optical, one cable for two devices, one cable for two devices, etc. It spreads the draw across the internal power buss inside the supply.
My question is does it matter how i setup my power supply? regards to using only 2 power cable to support 2 hard drives, DVD-Burner, and Floppy Drive, a hard drive cooler, and 2x120mm case fans, or should be using like 3(or even 4) power cables within the power supply? does it matter how this is layout. i have a Vantec Stealth 420W power supply(comes with liek 5 power cables). cause if i am over working 2 power cables please tell me or even if i'm not Thank You.

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic