Asus Z8PH-D12 SE/QDR - Manual (Page 43)

ASUS Z8NH-D12 Series 2-25
4. LAN controller setting (3-pin LAN_SW1, LAN_SW2)
These jumpers allow you to enable or disable the onboard Intel ® Intel
82574LGigabit LAN controllers. Set to pins 1–2 to activate the Gigabit LAN
feature.