Codex App 26.609.30741 causes severe system-wide lag on macOS

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

26.609.30741

What subscription do you have?

ChatGPT Pro ($100/month)

What platform is your computer?

Darwin 25.5.0 arm64 arm

What issue are you seeing?

The current Codex App version is causing severe system-wide performance degradation while it is running. The machine becomes extremely sluggish, and Codex itself becomes effectively unusable.

Observed behavior:

• Codex becomes very slow to respond during normal use.
• The rest of the system also becomes noticeably laggy while Codex is active.
• The overall experience reaches a point where the app cannot be used productively.

I searched existing issues and saw related reports such as #12709 and #25779, but this is still happening on the current Codex App build listed above, so I wanted to report the current Pro-user impact clearly.

What steps can reproduce the bug?

1. Open Codex App 26.609.30741 on macOS.
2. Use it for a normal coding session with tool execution and ongoing conversation.
3. Continue working until Codex begins to slow down.
4. Observe that both Codex and the broader system become heavily lagged, eventually making the app effectively unusable.

I do not yet have a smaller deterministic reproduction case, but the issue happens during normal Codex usage rather than a deliberately unusual workload.

What is the expected behavior?

Codex should remain responsive during normal usage, and running Codex should not make the rest of the operating system feel unusable.

A Pro user should be able to run sustained Codex sessions without the app degrading into a state where the entire system becomes sluggish.

Additional information

• Subscription: ChatGPT Pro ($100/month)
• Codex CLI available in the same environment reports: codex-cli 0.130.0
• Related open issues found before filing: #12709, #25779

I am happy to provide logs, diagnostics, or additional system details if the maintainers point me to the preferred collection steps.