Windows 10: 100% dGPU usage from Desktop Window Manager after disabling monitors attached to iGPU

Specs: ROG STRIX Z690-A GAMING WIFI D4, Intel i7 12700k, RTX3080, Windows 10 Pro 22H2 19045.2130 but this has been a persistent issue on all Windows/driver versions since building this PC a year agoWhen I disable monitors connected to my iGPU, leaving only my dGPU screens enabled, I get 100% dGPU usage from Desktop Windows Manager dwm.exe and horrible stutters, even when just moving windows around on the desktop.Steps to reproduce:1. Configure displays so that either only iGPU monitors are enabled, or there is a mix of iGPU + dGPU monitors enabled2. Reboot PC3. Run any 3D application, incl

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Multi-Monitor and iGPU and dGPU usage/load

Hello, I have trouble getting my iGPU to do work when the dGPU is set as "main display".

I have an iGPU Intel HD4000 on my 3770k CPU, I also have a dGPU Nvidia GTX690 in a Multi-Monitor setup. Connected to my GTX690 are 3 monitors, and connected to my HD4000 is a 4th accessory display.

What happens is that when I play a video using VLC on the monitor connected to the iGPU, all content is actually rendered on the dGPU, then sent over the PCIe bus to the iGPU and displayed from there. I don't want my dGPU adapter to have anything to do with
VLC when the window is not on those monitors. I want only my iGPU adapter to do work when VLC is on that respective monitor. If I move the VLC window over to a different monitor which is powered by another display adapter, I want that adapter to take over
the work.

Example - Playing a video on the Monitor connected to iGPU:

1. When iGPU is set as Main Display then; iGPU 17% usage, dGPU1 0%, dGPU2 0%.

2. When dGPU is set as Main Display then; iGPU 18% usage,
dGPU1 8%, dGPU2 0%.

In the first case where the monitor connceted to the iGPU is set as main display, everything works as I want it, only the iGPU does work as it outputs the video to its monitor. But I don't want to have my iGPU as Main Display, I want the dGPU as Main.

In the second case where a monitor connceted to the GTX690 is set as the main display, dGPU1 is at 8% even though no monitor connceted to this Dispay adapter is displaying anything.... For some reason Windows10 lets the dGPU do all the work and pass the
result to the iGPU which then displays it. I want the iGPU to do all the work.

How can I assign a different Display Adapter to a program, other then the "Main Display" (which all programs default to, regardless of which monitor they actually appear on)???

Nvidia has something called "Nvidia Optimus" but is only available for mobile devices. But this is not available for desktop. Does Win10 have something like it where I can pick which GPU a program will use?

 

Disabling iGPU in windows 10

Ah, had that multi display option disabled. Currently installing clean windows maybe that was the problem. What version of windows 10 are you on btw?

 

Disabling iGPU in windows 10

I think it is called Intel Multi Display.
Basically, if it is disabled, then your iGPU is completely disabled (will not even show in device manager).
If you enable it - then your iGPU becomes your primary adapter, and dGPU - secondary. Because of that your monitors will start to initialize from iGPU to dGPU too.
I just tried it on my PC, and it works as it should even without disabling multi-monitor feature, e.g. if I have something plugged into my iGPU video output, then I have that as my primary display, and if I disconnect it - my other display(connected to dGPU) becomes primary.