What exaclty is ErP in BIOS?

[Solid_Crimson]

Should I leave this disabled or enable s4+s5 or enable s5?

What exactly is this setting?

 

[i7Baby]

ErP Support determines whether to let the system consume less than 1W of power in S5 (shutdown) state. When the setting is enabled, the following four functions will become unavailable: PME Event Wake Up, Power On By Mouse, Power On By Keyboard, and Wake On LAN.