"In X8DTT MB, ""Main Switch Override Mechanism"" is a function to enable the delay of the main power shut down after pushing power bottom for 4 or more seconds to prevent accidental shut down from single push the power bottom.
Where to enable this option or change the seconds? Or it is OS dependent?"
"Please refer to user manual page 4-5.
http://www.supermicro.com/manuals/motherboard/X58/X8DTT.pdf
The option is 4_second_override or Instant_Off. You cannot change the seconds.
"