Is the laptop as good as they say it is?

I'm Planning to buy a lenovo y50 with Gtx860m. I have many doubts regarding the laptop.First of all is the 4gb version of Maxwell architecure. I read somewhere that all the 4gb versions are of keplar architecture. And how is the laptop performing with the latest games such as Witcher 3, GTA 5, Arkham Knight and how will it perform regarding the games to be released in the future.

GTX 860m

Witcher 3 - Will run at a minimum 35 FPS on low and medium settings. It will underperform (below 20 FPS) on higher settings

Arkham Knight - Will run at a minimum 35 FPS on low and medium settings, and around 25 FPS on High

GTA V - Will run at a minimum 35 FPS on low, medium and high settings