The LG G2 uses something called Graphic RAM to help extend battery life on the device; the name Graphic RAM is LG's own term for a technology called Panel Self Refresh. It comes into play when you are looking at the display on the phone and nothing is moving. This could happen while reading a website and the screen is static...
Source: http://www.phonearena.com/news/How-Graphic-RAM-helps-the-LG-G2-add-10-battery-life-on-a-single-charge_id46195
Source: http://www.phonearena.com/news/How-Graphic-RAM-helps-the-LG-G2-add-10-battery-life-on-a-single-charge_id46195