The dirty little secret of GPU marketing is that laptop graphics chips are never as powerful as you'd think. Think you're going to run a game maxed out at 2K resolution with the GeForce GTX 880M in your laptop? Think again—even if it's no trouble for a desktop-grade GTX 780.
But this year, Nvidia may be starting to fix those lying digits: The new GeForce GTX 980M delivers 75% of the power of a "real" GTX 980 desktop graphics card. That means everything from Battlefield 4 to Watch Dogs is playable at 2560 x 1440 resolution on ultra settings. (That's pretty awesome.)
Source:Nvidia GeForce GTX 980M: A Graphical Leap For Gaming Laptops