Which video drivers to use for Y50 ? Intel or NVidia ?

I have a Y50 which comes with an NVidia 860M card and I'm currently using Windows 10 64bit. Which drivers should I use for video/graphics ? Intel HD Graphics 4600 or NVidia (latest ones for 860M) ?

Normally I would assume that NVidia is superior to Intel, but when I install ONLY NVidia drivers, Windows still goes ahead and installs Intel HD Graphics 4600 in the background automatically, causing me to have BOTH drivers installed simultaneously.

Another possible issue I noticed was that if I have ONLY NVidia drivers installed, the possible display resolutions listing in Windows Display Settings for me are just 1024x768 and 1920x1080, and the former is the "recommended" resolution !!. However if I have the Intel drivers installed too, I get a whole bunch of other possible resolution options too.

Having both installed simultaneously is causing some other HDMI out issues for me, which I want to solve this. Help ?

 

Arent you supposed to use both? Nvidia has optimus meaning it uses the intel for non-graphics intensive tasks, and when you're gaming it'll switch to the nvidia.