Optimus disable onboard possible?

[okieiam]

Hi, in my Lenovo Yoga Phoenix ScureCore unlocked Anvandce page, there are option about IDP, PEG, mux, muxless, VD port etc. I don't remember just mimic around and disable onboard.
So the system loss display but still boot and I run VNC and discover that HD 5500 GONE system running on NVIDIA only.
May be I am selecting some thing not very fine like VD port or the setting is just to be cuztmized by each OEM?
It is possible to have output display when disable onboard IGPU in Optimus. If yet then what is the key setting?

 

[Solandri]

Most switchable graphics on laptop (Nvidia Optimus and the AMD equivalent) work by having the Intel integrated graphics always driving the screen. The Nvidia GPU acts as a co-processor. A game which uses the Nvidia GPU will use it to render a frame, then that completed frame is sent to the Intel GPU for display. (Vsync is essentially always on.) If you disable the Intel GPU, you will lose the ability to display directly to the screen or a monitor because the Nvidia GPU has no way to directly send info to the display.

There are some very rare laptops which allow you to switch whether the Intel or Nvidia GPU drives the screen. These have a setting in their BIOS letting you pick which GPU to use. More than likely whoever programmed the BIOS for that laptop assumed the advanced page would be disabled, so didn't bother disabling the individual features which would be useless. When you enabled the advanced page, you got access to "features" which would essentially make the laptop useless.

There are also a few laptops which use the Intel GPU to drive the built-in screen, but the Nvidia GPU to drive the HDMI port. The way you can tell is that some old games were programmed back when computers only ever had one GPU. So they will search the computer for the GPU, and stop after they find one. In Optimus laptops this is the Intel GPU (since it drives the screen). And it is impossible to use the Nvidia GPU in these games - they will only run on the Intel GPU. But on these few laptops, if you plug in an external monitor and disable the built-in screen, suddenly the game will run on the Nvidia GPU.

 

[virgosun]

Wow thank @Solandri for your fulfilling answer. About dGPU drive HDMI, some one told me the same thing as your answer. But how do I know if my laptop is of the rare cares where Nvidia GPU drive the HDMI port in Bios setting

 

[velo3100]

The way you can check if the igpu is disabled is by going to your device manager. It will display all the gpus under display driver. If the igpu is disabled, it will have an a red x next to it.