Windows App causes elevated Desktop Window Manager (dwm.exe) GPU usage when visible on multi-monitor high-refresh setup

What version of the Codex App are you using (From “About Codex” dialog)?

26.305.950.0

What subscription do you have?

Pro

What platform is your computer?

Microsoft Windows NT 10.0.26200.0 x64

What issue are you seeing?

When the Codex desktop app window is visible on screen, Desktop Window Manager (dwm.exe) GPU usage rises significantly on Windows.

On my system:

• if Codex is visible, dwm.exe rises to roughly ~8-10% GPU (sometimes higher in Task Manager snapshots), and the Codex app also uses GPU

<img width="1101" height="423" alt="Image" src="https://github.com/user-attachments/assets/8035617d-3e30-47b4-90a0-203543dcea4f" />

• if I minimize Codex (without closing it), both Codex GPU usage and dwm.exe GPU usage drop sharply, close to zero

<img width="1124" height="811" alt="Image" src="https://github.com/user-attachments/assets/cfc12742-86c3-4b1f-bece-9e78dbf2ee2f" />

This strongly suggests the problem is related to visible window rendering / composition rather than background work, network activity, or the process merely being open. All displays are now connected to the NVIDIA GPU, and this Codex-visible-window behavior still reproduces.

https://github.com/user-attachments/assets/da56a3d9-b6a9-42f8-84fd-7f5bb000b1e5

Sorry the clip is only ~5 seconds because of the 10 MB upload limit, but I hope it is enough to show how sharply GPU/DWM usage drops when Codex is minimized

What steps can reproduce the bug?

1. Launch the Codex desktop app on Windows
2. Keep Task Manager visible and sort by GPU usage
3. Leave Codex open and visible on screen
4. Observe that both Codex and Desktop Window Manager use noticeable GPU
5. Minimize Codex without closing it
6. Observe that GPU usage for both Codex and 'dwm.exe' drops sharply, close to zero

This appears to depend on the Codex window being visible rather than the app simply running in the background

What is the expected behavior?

_No response_

Additional information

System:

• Laptop: Lenovo model 83F5 (Legion-class system)
• Codex package: OpenAI.Codex_26.305.950.0_x64__2p2nqsd0c76g0
• Windows: 25H2, build 26200.7840
• NVIDIA GPU: GeForce RTX 5080 Laptop GPU
• Driver: 32.0.15.9571
• Driver date: 2026-02-27
• Intel GPU: Intel(R) Graphics
• Driver: 32.0.101.8243
• Driver date: 2026-01-26

Display / graphics configuration:

• All three displays are now connected to NVIDIA according to Windows Advanced Display
• Internal panel: ATNA60HU01-0, 2560x1600 @ 240 Hz
• External displays: 2560x1600 @ 144 Hz + 2560x1600 @ 144 Hz
• Lenovo graphics mode: Discrete
• Optimizations for windowed games: On
• Variable refresh rate: On
• Hardware-accelerated GPU scheduling: Off
• MPO workaround had already been applied on this machine (OverlayTestMode=5)