http://www.extremetech.com/gaming/152511-unreal-engine-4-looks-much-better-on-the-pc-compared-to-the-ps4
This one reminds me a lot Lord of The Ring: a mix in between Sauron and Balrog >E
This one is interesting too
http://www.youtube.com/watch?v=dO2rM-l-vdQ
Note that it is not image synthesis, but really Unreal engine 4. Nevertheless, it is precised that the engine run 4 times slower that normal speed, exploiting 100% of GTX680 processing capabilities. Hence, to run the game with its full power, it would need four GTX680 to get a real time playable demo
After small calculation it means "basically" and roughly just 12 Terra Flops a 14 billions of transistors... just a "small" GFX setup