High CPU usage on Windows desktop app compared to Claude Code

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

26.707.31428

What subscription do you have?

Plus

What platform is your computer?

Windows 11 Intel Core i7-4790 (4 cores / 8 threads)

What issue are you seeing?

The Windows desktop app consistently uses a significant amount of CPU while working on projects, even during relatively normal development tasks. On the same machine and on the same codebase, Claude Code performs the same operations with much lower CPU usage.

This makes the desktop app noticeably noisier (fans running continuously) and less pleasant to use during long coding sessions.

Environment

OS: Windows 11

CPU: Intel Core i7-4790 (4 cores / 8 threads)

ChatGPT Windows desktop app (latest available version)

Project: medium-sized .NET solution

Observed behavior

After opening a project and working with Codex:

CPU usage remains consistently high.

Multiple ChatGPT processes accumulate significant CPU time.

Cooling fans stay active almost continuously.

Windows Defender is not the primary cause (excluding the project directory did not materially change the behavior).

Example process list:

ChatGPT.exe
CPU Time:
348.94
98.61
36.89
...

Comparison

Running the same development workflow with Claude Code on the same machine:

CPU usage is substantially lower.

Fans rarely spin up.

Overall system responsiveness is noticeably better.

The difference is large enough that it seems to be related to the desktop application's architecture or background activity rather than the AI inference itself.

Expected behavior

Lower idle/background CPU usage.

Reduced renderer/background processing when no active work is being performed.

CPU consumption comparable to other coding assistants during equivalent tasks.

Additional notes

If useful, I can provide:

Task Manager screenshots

Process Explorer / Process Monitor traces

Windows Performance Recorder (WPR) traces

Reproduction steps

Application version and diagnostic logs

What steps can reproduce the bug?

Open Codex

What is the expected behavior?

I wouldn't expect the application to consume a high amount of CPU while it's idle.

Additional information

_No response_