Asus Motherboard A8N-SLI SE - Manual (Page 148)

6-4 Chapter 6: NVIDIA ® SLI™ technology support
5. Align and insert the SLI flexible cable connectors to the goldfingers on
each graphics card. Make sure that the SLI flexible cable connectors
are firmly in place.
6. If using a 20-pin ATX power connector, connect a 4-pin ATX power
cable to the EZ Plug™ labeled EZ_PLUG on your motherboard.
The onboard red warning LED lights up if you do not plug a 4-pin ATX
power cable to the EZ Plug.
SLI flexible cable
ASUS EZ Plug™
7. Connect a VGA cable or a DVI-I cable to the graphics card installed on
the blue PCI Express slot.