I want to buy a new notebook, and to be honest I want it to run all modern games with as high details as possible. Recently I came across a notebook that had in its graphics card section written: "NVIDIA GeForce GTX 860M + Intel HD Graphics 4600". And my question is - does having such combination have a real impact on computer gaming performance? Is it possible that those two graphics cards cooperate and such combination is really faster than NVIDIA GeForce GTX 860M alone? Or having two graphics cards has other advantages and gaming performance is not one of them?
You can't combine them together. nVIDIA optimus will pick the nVIDIA GPU for games.
But the 860M is still not fast enough to run modern games with good performance. You can use a desktop GPU via an eGPU adapter to have a better performance. If the Desktop GPU gets too slow for new games in 2016/2017 you can replace the GPU with a newer model.