content: Total TDP is 15W. No way you're using 100% CPU capacity to render a movie. My old AMD X6 underclocked to 1.2 GHz uses only 8% CPU to run VLC to render a 1080p mp4 movie encoded with H264. My graphics card is old as the hills, so not much help there with rendering. You're telling me CPU that's 8 years newer and running at double the clock speed will consume 100% CPU utilization? ( and thereby utilize all 15W of TDP)? No way. Even if we lived in bizarro world where a brand new mid-range CPU/GPU combo would need 40% CPU utilization to play a movie, add the screen power consumption and fan, then you're talking 8 Watts. 46 WHr * .9 / 8  = 5.175 hours. I don't think the projections are far off.