If the sun is beginning to go down on the era of 1080p gaming, the Lenovo IdeaPad Y900 is the absolutely stunning sunset that marks the end of the day. OK, that's a little dramatic, as full HD is here for a long time, but when it comes to high-end gaming, 4K has gone from expensive and pointless novelty to cutting-edge must-have. While the $2,499 or...