[Windows][26.924.2738.0] Regression vs 26.917.9434.0: main ChatGPT.exe spikes to 30–40% CPU and UI intermittently freezes / becomes Not Responding #48665

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

26.924.2738.0 — MSIX package OpenAI.Codex_26.924.2738.0_x64__2p2nqsd0c76g0
Embedded browser binary: ChatGPT.exe = Chromium 154.0.8037.57 (crashpad annotation ver=154.0.8037.57; the package contains 154.0.8037.57.manifest)

What subscription do you have?

Omitted for privacy; not relevant to this UI performance report.

What platform is your computer?

Microsoft Windows NT 10.0.22621.0 x64 (Windows 11 Home 22H2)

• CPU: Intel Core i7-11370H (4 cores / 8 threads)
• RAM: 16 GB
• GPU 0: Intel Iris Xe Graphics — driver 32.0.101.7088
• GPU 1: NVIDIA GeForce RTX 3050 Laptop GPU (4 GB) — driver 32.0.15.8183 (hybrid graphics laptop)
• Also present: a MuMu Virtual Display Adapter (virtual display from an Android emulator installed on this machine)
• System language: zh-CN

What issue are you seeing?

Performance regression after updating to 26.924.2738.0.

A/B on the same machine, same drivers, same workload:

During a freeze:

• Total system CPU rises to ~50–70%
• The main ChatGPT.exe process spikes to ~30–40% of total CPU (≈ 2.5–3 of the 8 logical processors)
• Task Manager sometimes marks that ChatGPT.exe as Not Responding
• After the freeze passes, CPU drops back down; it recurs later
• RAM is not exhausted (~50–60% used) and the system-wide handle count stays around 110k–150k, so it does not look like memory or handle exhaustion

Windows Event Log evidence (Application log, Windows Error Reporting, Event ID 1001, event name AppHangTransient, faulting app ChatGPT.exe):

2026-09-27 17:12:47 (local)   ChatGPT.exe 154.0.8037.57   <- current build
2026-09-27 17:08:02 (local)   ChatGPT.exe 154.0.8037.57   <- current build

The MSIX deployment log (Microsoft-Windows-AppXDeploymentServer/Operational) shows 26.924.2738.0 was registered today at 16:50 local time, i.e. both recorded hangs happened within ~20 minutes of the update.

For transparency: the same log shows six AppHangTransient events on 2026-09-24 (19:38–22:54 local) for browser version 153.0.8010.53, which corresponds to the previously installed 26.917.9434.0. Subjectively that build was smooth in day-to-day use on this machine; the freezes on 26.924.2738.0 are far more frequent and severe.

The affected process is the desktop main/browser process (observation, not a proven cause):

Command line of the spiking / Not Responding instance (live capture today; PID varies per launch, example 16036):

"C:\Program Files\WindowsApps\OpenAI.Codex_26.924.2738.0_x64__2p2nqsd0c76g0\app\ChatGPT.exe"

It has no --type= argument at all, i.e. it is the main/browser process (CrBrowserMain equivalent). All other ChatGPT.exe instances on the same machine carry --type=renderer, --type=gpu-process, --type=utility or --type=crashpad-handler.

What steps can reproduce the bug?

1. On Windows 11, update Codex Desktop from 26.917.9434.0 to 26.924.2738.0.
2. Launch the app and use it normally (open conversations, send prompts).
3. During ordinary interaction the UI intermittently stutters or freezes for seconds at a time.
4. While frozen, Task Manager shows the main ChatGPT.exe (the instance with no --type= in its command line) at ~30–40% CPU with total CPU at ~50–70%; sometimes "Not Responding".
5. The freeze passes and CPU drops back; it recurs later during continued use.

No single deterministic trigger has been isolated yet; it is intermittent.

What is the expected behavior?

The UI should remain responsive during normal use, as it did on 26.917.9434.0 on the same hardware.

Additional information

• The Intel graphics driver (32.0.101.7088) was already updated before the smooth 26.917.9434.0 testing, so the GPU driver did not change between the two test conditions — only the app version did.
• No root cause is claimed here; the main-process CPU correlation is an observation. I can capture more data (WPR/ETW trace, process dumps, etc.) on request.
• Similar but not identical existing reports: [Windows] Codex Desktop severe UI lag, input delay, and intermittent Not Responding while browser version remains responsive #43726 (Windows UI lag + intermittent Not Responding), [Windows Desktop 26.917] Every completed reply hangs UI; reasoning-summary disable ignored after restart #48033 (26.917: hang at every completed reply, main_thread_jank_snapshot, main-thread JS stacks in dumps), [Windows 26.924] Every cold startup stalls on Loading; restarting only app-server restores UI #48466 (26.924: cold-start stuck on Loading, app-server restart workaround), [Windows][26.924.2738.0] Repeated startup/loading hang; Event ID 1002 #48457 (26.924: repeated startup hang, Event ID 1002), and older Windows main-process CPU reports [Windows desktop] CrBrowserMain consumes one CPU core while watching a delete-pending directory; restart clears it #44960, [Windows][26.810.6296.0] Electron main process busy loop causes system-wide mouse stutter; full exit fixes it #38716, Windows Desktop 26.803.5235.0: UI process sustains ~90–102% CPU while idle #37372, Codex Desktop v26.527.30818 sustained main-process CPU burn after update #25159.
• What appears new in this report: (a) explicit same-machine A/B regression 26.917.9434.0 → 26.924.2738.0, (b) the CPU spike localized to the main/browser ChatGPT.exe (no --type= flag), (c) WER AppHangTransient timestamps within ~20 minutes after the 26.924.2738.0 update.
• Timestamps and PIDs vary per session; paths shown are standard install paths. No logs or dumps are attached because they contain private data; they can be shared through a private channel if needed.