This connecter is used for extra power to the processer.
PCIe 16x Video Card
A lot of hard disk docking stations use these kind of power supplies.
A six in or in some cases, eight pin, power connection are used by various video cards which are almost universally PCI Express cards. These are needed to supply power when the card's require more then 75 watt power provided by the PCI Express slot itself. These are the six pin and eight pin 12v connections.
A PCI Express, Version 1 high-end video card using PCIe x16 slots.
4 pin and 6 pin. 6 pin provides power for the external device.
S-Video
S-Video
A regular ATX motherboard uses a single 20-pin P1 connector with optional 4-pin auxillary power connector
Is used by High-end video card using PCIe x 16 slots to provide extra voltage to the card.
A PCI Express, Version 1 high-end video card using PCIe x16 slots.
which of the following device uses a 6-pin Mini DIN connector a. ps/2- style mouse
"The 6-pin PCIe connector provides an extra +12 V for high -end video cards using PCI Express, Version 1 standard." Source:A+ Guide to hardware by Jean Andrews pg. 12