[Windows][Codex Beta 26.727.4816.0] Idle app pegs CPU and causes large idle network increase

What version of Codex is running?

Microsoft Store Windows desktop app package:

OpenAI.CodexBeta_26.727.4816.0_x64__2p2nqsd0c76g0

Start menu label: ChatGPT (Beta)

Stable package also installed:

OpenAI.Codex_26.901.2854.0_x64__2p2nqsd0c76g0

What platform is your computer?

Windows 11 x64 desktop, Microsoft Store app install.

What issue are you seeing?

Codex Beta becomes extremely resource-intensive while completely idle, with no Work/Codex thread or active task running.

The problem is reproducible on demand and persisted after:

1. terminating the full Codex Beta process tree and restarting the app;
2. resetting the complete Codex Beta local browser/profile state under the Microsoft Store package data directory.

Measured idle CPU

Initial 10-second idle sample:

• ChatGPT (Beta) main process: ~78.6% CPU

After full process-tree termination and restart:

• ChatGPT (Beta): ~103% CPU, ~1.5 GB RAM
• codex.exe: ~67.5% CPU

After a full local profile reset and relaunch:

• ChatGPT (Beta): ~100.3% CPU, ~1.1 GB RAM
• codex.exe: ~40.6% CPU

The reset therefore did not resolve the issue.

Process ownership

The high-load process tree is inside:

C:\Program Files\WindowsApps\OpenAI.CodexBeta_26.727.4816.0_x64__2p2nqsd0c76g0\app\

Confirmed child processes include:

• ChatGPT (Beta).exe main process
• renderer processes
• GPU process
• network.mojom.NetworkService
• codex.exe

The codex.exe command line included:

features.code_mode_host=true app-server --analytics-default-enabled

Network behavior while idle

A 60-second PID-specific TCP survey confirmed outbound connections owned by Codex Beta processes, including the Codex Beta network service and codex.exe.

A controlled adapter-byte comparison was then performed with the machine otherwise idle:

Beta closed, 60 seconds

• Received: 106 KB
• Sent: 186.4 KB

Beta open and idle, 60 seconds

• Received: 28,177 KB
• Sent: 3,017.7 KB

Difference

• Received increase: 28,071 KB
• Sent increase: 2,831.3 KB

This is approximately 27.4 MB additional received traffic and 2.8 MB additional transmitted traffic during a one-minute idle comparison. The received traffic was roughly 266x the Beta-closed baseline.

I understand this adapter-level comparison does not prove every byte belongs to Codex Beta, but Codex Beta was the controlled change between the two test windows, and separate PID inspection confirmed active outbound connections from executables inside the Codex Beta package.

What steps can reproduce the bug?

1. Ensure ChatGPT (Beta) / Codex Beta is fully closed.
2. Launch ChatGPT (Beta) from the Microsoft Store app package OpenAI.CodexBeta_26.727.4816.0_x64__2p2nqsd0c76g0.
3. Do not open or run any Work/Codex thread or task.
4. Leave the app idle for 10–60 seconds.
5. Measure CPU for the process tree.
6. Observe the main ChatGPT (Beta) process consuming around one full CPU core and codex.exe also consuming substantial CPU while idle.
7. Optionally compare network adapter byte counters with Beta closed vs Beta open and idle; the reproduced test above showed ~106 KB RX closed vs ~28,177 KB RX open/idle over 60 seconds.

What is the expected behavior?

When no task or thread is active, Codex Beta should remain near-idle CPU and should not cause a large sustained increase in network activity.

What is the actual behavior?

The app repeatedly consumes around a full CPU core while idle, with additional substantial CPU from codex.exe, and the machine shows a large increase in network traffic when Beta is open and idle.

Additional information

This appears related to other Windows Codex desktop regressions involving Chromium/GPU/process behavior, including issue #34133, but this report is distinct because the failure reproduces while completely idle and persists after a full local profile reset.

Support has confirmed that the affected ChatGPT/Codex account currently shows 0% Codex usage consumed, so the local CPU/network defect should be treated separately from account-side Codex quota usage.

Available diagnostics if requested:

• ETL network trace
• converted trace text
• PID-specific TCP connection CSV
• process-tree output
• exact PowerShell measurement commands and timestamps

Incident date: 2026-09-04, America/New_York timezone.

Reproduce the idle behavior from the Microsoft Store package OpenAI.CodexBeta_26.727.4816.0_x64__2p2nqsd0c76g0, observing ChatGPT (Beta).exe, codex.exe, and the network service. Compare the process-tree CPU and adapter traffic with Beta closed, then review the related Windows process regression in issue #34133. Done means idle use returns near-zero CPU with no large sustained network increase.