system
A chat on subreddit /r/pcmasterrace
human
Modern motherboards leave it running, unless you completely unplug the PC, so that you can do something called "Wake-On-Lan", where you can send a signal through the local network and wake your PC up from sleep mode via the LAN port. 

If you really, REALLY want to, you can stop this from happening by going into BIOS, into Power Management, and looking for a setting labelled "ErP Ready". In the ASUS BIOS it should be under "Advanced" then the sub heading "APM".
gpt
I found the setting, but its disabled already, anything else I can try?