Lenovo y480 questions

Howdy everyone. I've been looking at picking up a laptop. I've narrowed it down to the Acer Aspire M5, and the Lenovo Y480. My question is this. Lenovo's website has this model at 799, and it says "4.5 lbs" and then I found this one on New Egg Can anyone explain the differences, or the actual weight of a Y480?