MSI NLX LX3 Manual page 26

This is used to enable/disable the keyboard power on feature. This
mainboard supports keyboard power-on feature. The keyboard needs to
have a power supply which can provide sufficient 5V standby power for
both the keyboard and the mainboard.
Note: a. To be able to use this function, you need a power supply that
provide enough power for the keyboard power on feature.
(750 ma power supply with 5V Stand-by)
b. Consult power supply vendor about the 5V stand-by for your
keyboard power consumption.
c. If JVCC is short, then you cannot set the BIOS setting of
Keyboard/Mouse Wake-up function to Enabled. It will not turn the
system on. If this happen, you must clear the CMOS.
JVCC/JVSB
2-21
JVCC JVSB
Function
Enabled
Disabled