100% dGPU usage after disabling monitors attached to iGPU

[captainspork]

Specs: ROG STRIX Z690-A GAMING WIFI D4, 12700k, RTX3080, Windows 10 Pro 21H2 19044.2130

When I disable my iGPU monitors, leaving only my dGPU monitors 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 enabled
2. Reboot PC
3. Run any 3D application, including looking at an online video
4. Disable the monitors connected to the iGPU, leaving only dGPU displays enabled
5. There will now be near constant 100% utilization of the dGPU

This issue results in me needing to leave one of the iGPU monitors enabled at all times, otherwise my dGPU is maxed out and the computer is unusable. The only workaround I've found to allow me to use monitors connected to the dGPU while leaving iGPU monitors disabled is to switch to the dGPU monitors and reboot the PC. Any time the iGPU is used after a reboot, this issue will arise if all of the screens connected to it are disabled.

I had hoped that a year of BIOS and driver updates would have fixed this issue, but it still persists. Would be really grateful for any advice, or if this can be forwarded to engineering. Thanks.

[RogScott]

Go to Graphics settings, find "Hardware Accelerated GPU Scheduling" feature, and disable it. Reboot will be required. See if that eliminates the DWM 100% usage.

[captainspork]

RogScott wrote:
Go to Graphics settings, find "Hardware Accelerated GPU Scheduling" feature, and disable it. Reboot will be required. See if that eliminates the DWM 100% usage.

Thanks for the suggestion. This did actually reduce the GPU usage however it didn't eliminate the stuttering when moving windows around. Now there are smaller but more frequent (probably 5-10 times per second) stutters when dragging windows around compared to the larger slightly less frequent stutters with hardware-accelerated GPU scheduling enabled.

[RogScott]

Sorry that didn't resolve it. I recently ran into high DWM usage (though not with any discernable performance impacts) when I loaded the nvidia 522.25 driver, and turning off the Hardware Accelerated GPU Scheduling (HAGS) resolved it -- so hoped it would help you.

Has this problem always existed since your machine was new? I've seen a lot of people say it happened after certain Windows updates, so if it started recently you might look at your update history and see if anything coincides.

I assume you've already updated the video drivers to latest (both iGPU and dGPU). Though sometimes that backfires -- I never had the issue until I updated to the latest nvidia driver (522.25) . Many people have reported it with 522.25 -- some with performance impacts, others with high usage% in task manager but no performance problem.
Some users reported resolving it by turning HAGS off (as I did), others were able to resolve it with DDU and a rollback to earlier Nvidia driver.

Good luck -- it sucks to build a nice machine and then have recalcitrant issues like this.

[captainspork]

RogScott wrote:
Sorry that didn't resolve it. I recently ran into high DWM usage (though not with any discernable performance impacts) when I loaded the nvidia 522.25 driver, and turning off the Hardware Accelerated GPU Scheduling (HAGS) resolved it -- so hoped it would help you.

Has this problem always existed since your machine was new? I've seen a lot of people say it happened after certain Windows updates, so if it started recently you might look at your update history and see if anything coincides.

I assume you've already updated the video drivers to latest (both iGPU and dGPU). Though sometimes that backfires -- I never had the issue until I updated to the latest nvidia driver (522.25) . Many people have reported it with 522.25 -- some with performance impacts, others with high usage% in task manager but no performance problem.
Some users reported resolving it by turning HAGS off (as I did), others were able to resolve it with DDU and a rollback to earlier Nvidia driver.

Good luck -- it sucks to build a nice machine and then have recalcitrant issues like this.

Thanks. Unfortunately yes, this problem has persisted ever since I built the machine about a year ago, so it doesn't seem tied to a particular driver/BIOS/OS version. I think it may be a general bug in Windows.