If I leave my pc idle for I think it's like 5 hours it hibernates automatically, it's a setting on the mobo but I don't know how to change it. Google just gives me people having shutting down isses.
My pc stanbys whenever I am gone for more then 30 mins its a great feature for power saving. I also put my cpu into powersaving mode and watch the polar bear spin the globe for hours on end.