Asus RS724Q-E6/RS12 - Manual (Page 53)

ASUS RS720Q-E6/RS12, RS724Q-E6/RS12 4-7
3. DDR3 voltage control setting (4-pin LVDDR3_SEL1; LVDDR3_SEL2)
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.