I have a Dell Inspiron 15 7559 laptop. i7 6700hq + GTX 960M (4GB) + 8GB RAM. All good.
Yet when playing games, even older titles such as Skyrim, Call of Duty 4, Dishonored, etc... there are lag spikes every 10-15 seconds or so where the game just freezes for 2-3 seconds, and then returns to...