I'm going to guess that you have to physically remove the discrete GPU in order to install the Intel drivers, but once they're installed you can plug the discrete GPU back in.
No, I've personally never needed to do that... Just a matter of installing the right drivers.
Running windows 10 x64. cheers!
So just to show the performance difference; here is a graph depicting how my GPU and iGPU are being used depending on the resolution of the video I am watching (each video was viewed for approximately two minutes)...
Notice how the iGPU usage increases as the quality of the video becomes better (positive correlation). It increases to around 40% when watching 1080p content... This allows me to use Madvr settings that otherwise would not be possible, without dropped/delayed frames, had I been using the GPU alone (especially when up-scaling 720p content to 1080p).
Anyway; the latest driver from Intel for the HD4600 is below...
Download the .exe, install it, restart the computer as prompted after it finishes, then run SVP 4.0 Free Edition, Right-Click, Application Settings, GPU Acceleration, and select HD 4600...