Question "Not supported with G-Sync LCD panel" - Alienware 15 r3

[Tutoh1]

Hello,
I'm the process of buying a secondhand Alienware 15 r3 laptop. On my first visit to the seller, I was disappointed to discover that even though the laptop had both a iGPU and a dGPU, there was no way to switch (MUX switch) the graphics from the dGPU.
Pressing Fn+F7 brought an error message on the screen - "Not supported with G-Sync LCD panel".

Information on this error message is REALLY sketchy online. Some say that the G-Sync LCD panel is hardwired to the dGPU and that the iGPU is connected to nothing. Some say that dGPU is connected to the G-Sync LCD through the iGPU. Some say that they got the MUX switch working after an intention ordering of bios update, iGPU drivers then dGPU drivers on a clean install.

I'm suspecting that if I connect an external 60hz IPS monitor to one of the display ports on the laptop and make it the only display, the Fn+F7 key will actually switch the graphics because the display is not a G-Sync LCD panel. Am I right on this?

If I'm right on this, does that mean that if I purchase this laptop, order a 15inch Alienware 60hz IPS screen and swap it with the FHD 120+hz screen currently inside, I will also continue to have MUX switch support and no G-Sync? The price for these screens is not outrageous.

 

[JohnBonhamsGhost]

both a iGPU and a dGPU, there was no way to switch (MUX switch) the graphics from the dGPU.
Pressing Fn+F7 brought an error message on the screen - "Not supported with G-Sync LCD panel".

usually this would mean that the iGPU does not support G-Sync and it would need to be disabled before switching.

Some say that the G-Sync LCD panel is hardwired to the dGPU and that the iGPU is connected to nothing

the iGPU does not get connected to a screen.
it is embedded in the CPU and while the CPU is installed the iGPU is fully functional.
whether you would need to disable the dedicated GPU in the BIOS to access the iGPU depends on the particular system design.

order a 15inch Alienware 60hz IPS screen and swap it with the FHD 120+hz screen currently inside

why would you want to switch the stock onboard 1080p 120Hz screen with a 60Hz variant?

 

[Tutoh1]

"whether you would need to disable the dedicated GPU in the BIOS to access the iGPU depends on the particular system design. "
There is definitely no option to disable the dGPU in the BIOS.
I've tried disabling the dGPU in the Device Manager. There is a screen refresh of some kind but the estimated battery life time remaining doesn't change. That says to me that the power draw is exactly the same as before, like the dGPU is still running.
On my Alienware 14, I get 45 minutes with 65% battery when running the GTX 765M and 1 hr 15 minutes when running the iGPU.

It strikes me as bizarre that Dell have designed it this way. No ability to actually turn off the dGPU to conserve power.

 

[RyleyI]

I think it's like some of the newer M series laptops, strictly dGPU. No option for the iGPU.