I recently bought a gaming laptop, asus rog g551jm with an nvidia geforce gtx 860m 2gb graphics card, i'm very happy with the overall gaming performance of my computer, but i was wondering if it is possible to upgrade the video card for a gtx 860m 4gb or a gtx 880m or a 4gb video card? I want this upgrade thinking in the "next gen" games, i'm not sure if 2gb would be enough to keep the actual performance level (graphics in high, all that stuff), thanks!
Laptop graphics tend to not be upgrade-able as the GPU is soldered directly to the circuitboard. You would have to buy a new laptop for a better video card.
Still doesn't solve your problem as you'd have to buy a new laptop, but if upgradeability is something you're concerned about, you could invest in one of the solutions from MSI or Dell/Alienware that lets you "dock" with a box that has a desktop GPU in it.