Asus RS924A-E6/RS8 - Manual (Page 58)

4-6 Chapter 4: Motherboard information
3. LAN controller setting (3-pin LAN_SW1)
These jumpers allow you to enable or disable the onboard Intel ® 82580EB
Gigabit LAN controllers. Set to pins 1-2 to activate the Gigabit LAN feature.
4. DDR3 voltage control setting (4-pin LVDDR3_SEL1; LVDDR3_SEL2;
LVDDR3_SEL3, LVDDR3_SEL4))
These jumpers allow you to adjust the DIMM voltage. Set to pins 1–2 to
select 1.5V BIOS control, pins 2–3 to select 1.2V Force or 3–4 to select
1.35V Force.