Task switching causes system-wide stuttering

Environment

• Codex Desktop: 26.707.9981.0
• Windows 11 Pro 25H2: 10.0.26200.8655, x64
• Bundled Chromium: 150.0.7871.115
• CPU: Intel Core i7-14700KF
• GPU: NVIDIA GeForce RTX 4070 Ti SUPER
• NVIDIA driver: 595.95

Issue

Switching to any task from the Codex Desktop sidebar causes severe, brief system-wide mouse and UI stutter.

The problem is not limited to rendering inside the Codex window. Pointer movement and general Windows UI responsiveness are affected during the task switch.

Crash evidence

Windows Event Viewer records an Application Error 1000 / MoAppCrash for ChatGPT.exe whenever tasks are switched.

Common fields:

• Exception code: 0xc06d007f
• Faulting module: unknown
• WER signature: PCH_84
• Package: OpenAI.Codex_26.707.9981.0_x64__2p2nqsd0c76g0

I recorded 142 matching crash events in approximately 38 minutes. Their timestamps correlated with task switching.

The same exception continued after reinstalling the application, using a newly started ChatGPT.exe PID.

Performance evidence

During one reproduced stutter:

• Interrupts peaked at approximately 505,233/sec
• DPCs queued peaked at approximately 60,232/sec
• Processor queue length reached 17
• CPU peaked around 52%

There was no corresponding resource exhaustion:

• Approximately 13.5 GB RAM remained available
• Maximum disk queue length was only 0.43
• Network DPC activity did not explain the spike
• The system uses the Ultimate Performance power plan

Troubleshooting performed

The issue persists after:

• Windows app Repair
• Windows app Reset
• Complete uninstall and reinstall
• Successful Appx Stage and Register operations
• Restarting Codex and reproducing with a new process
• Verifying that the C: and D: package paths reference identical application files
• Checking that no third-party DLLs are injected into ChatGPT.exe
• Restarting SteelSeries Sonar and clearing an unrelated 473,000-handle leak

Reinstalling did not change the installed version; it remains 26.707.9981.0.

Expected behavior

Switching tasks should not trigger a MoAppCrash, Windows Error Reporting activity, or system-wide pointer/UI stutter.

Related reports

• #33074
• #33202
• #29187
• #33258

This appears to be a regression in the current Windows desktop task hydration/rendering or Chromium/DWM presentation path.