I've got Alienware R4 i7 6820HK 

GPU: Nvidia 1070 - 7GB

I have no idea why when I press FN+F7 > I move to integrated graphics then I can feel the windows freezes even when you try to give a desktop refresh (without playing games or anything)

On the other hand, while I move again Fn+F7 > to Dedicated GFX - it has no problems... hmmm 

OS: Windows 10 Pro 

All drivers including BIOS are updated!

I have no idea why this happens!

PS: I also had installed previously win 10 home - the same problem.